Home

Please support mflenses.com if you need any graphic related work order it from us, click on above banner to order!
SearchSearch MemberlistMemberlist RegisterRegister ProfileProfile Log in to check your private messagesLog in to check your private messages Log inLog in

What's the best ~75-150mm zoom lens?
Post new topic   Reply to topic
Home   Manual Focus Lenses
View previous topic :: View next topic  


PostPosted: Sun Jan 16, 2022 1:13 pm    Post subject: Reply with quote
Dejan wrote:
Minolta 75-150mm is on top of my list, it's just that's even harder to decide to buy a zoom that's badly presented in the ad than a prime lens. More places things could go wrong, and probably much harder to clean the lens.

I can only speak about lenses I got or bought within Switzerland - I have tested several series of Minolta MD and early AF zoom lenses (MD 3.5/35-70, AF 28-135, AF and MD 70-210, AF 75-300 "big beercan"). On 24 MP FF there was no "lemon"; in fact is was very rare to see small differences even when pixel peeping. Nothing to worry about in "real life photography", for sure!


Dejan wrote:
I was considering the Canon as a temporary solution (much easier to find, plus comes at 2-3x lower prices so why not), but I didn't expect it'd do worse around 100mm, but rather have it as a sweet spot.

I have re-checked it at f=100mm, using a second sample - the results are the same (if not slightly worse). Therefore I would assume it's a real effect. I would say the Canon is a really good lens as well, especially because it has very little lateral CAs. I have been using it for hiking in the mountains (before I got the Minolta), and always been impressed about its "real-world performance".


Dejan wrote:
These tests were very interesting, thank you!

You're welcome!


Dejan wrote:
What would you say about distortion (where Minolta's doing relatively badly anyway) with the Canon?

I wouldn't say Minoltas are generally "doing badly" concerning distortion - but I haven't really compared many vintage lenses when it comes to distortion. Next week, I may be able to take a few of those 70(75)-150mm with me e. g. to Zurich and shoot a few really straight Swiss bank buildings Wink. Here, on the countryside, nothing's really straight anyway ... everything seems slightly slanting, sloping, warped, and buckled ...


Dejan wrote:
I'd guess it's similar. Another thing, would you know if there's visible improvement at 5.6 with the Canon? That'd be nice for handheld situations when using my non-stabilized camera.

No, it isn't. I just have checked ist. Even at f8 it's not yet as good as at f11. Vignetting of course is reduced when you stop down to f8.


Dejan wrote:
On the other hand, I'd expect much more copy variation with Canon lenses, maybe even decentering issue (which seems to be much less likely with the Minoltas, never happened to me so far).

I haven't checked a large number of Canon (n)FD lenses for sample variations, and thus can't really comment on that. Nevertheless, due to the well known issue of de-composing parts in their zoom- and focusing mechanisms (mostly IF and floating element focusing) I would expect much more problems with Canon (n)FD lenses than with Minolta MC/MD stuff. I have never seen Minolta lenses with disintegrated/decayed sliding surfaces.

Be aware that all three copies of the Canon nFD 70-150mm I have seen so far did have some fungus. One quite a lot, the other two only to a minor extent.

S

Last edited by stevemark on Tue Jan 18, 2022 4:23 pm; edited 1 time in total


PostPosted: Sun Jan 16, 2022 2:10 pm    Post subject: Reply with quote
Thank you very much for your kind reply, it's really helpful! The Canon seems to be pretty common lens, yet without much information. Now I have much clearer idea.


PostPosted: Tue Jan 18, 2022 4:22 pm    Post subject: Reply with quote
Cleaning some fungus on the nFD 4.5/70-150mm:

http://forum.mflenses.com/viewtopic,p,1559204.html#1559204

S


PostPosted: Mon Apr 11, 2022 12:25 pm    Post subject: Reply with quote
Well - a few days ago I got a nice looking sample of the Tamron 3.5/70-150mm (second, better computation - the 20A).
I have tested it against the Minolta MD-III which was the winner of my previous 70-150mm test (see my previous postings in this thread).

While the Tamron was marketed as an "1:3.5" lens, in reality it was pretty much an f4 lens. This is confirmed by the exposure time measured with my Sony A7II: wide open, the Tamron and Minolta had the same exposure times. Therefore I have labelled the corresponding corner crops with "f4", even though the lens nominally was set to "f3.5".

Both at the wide as well as at the long end the Tamron compares very well to the Minolta. However, around f=100mm the Tamron performs clearly worse than at 70mm or at 150mm. And at 100mm the Minolta really shines ...!

I have included also the results of the Nikkor-P 2.5/105mm (later and better Xenotar type). Comparing these humble zooms with one of the most famous Nikkors may seem a bit daring - but look carefully at the images Wink

CLICK TWICE ON THE IMAGE TO GET THE FULL RESOLUTION!



S


PostPosted: Mon Apr 11, 2022 4:50 pm    Post subject: Reply with quote
The Tamron doesn't perform so bad. The 105mm performance is a bit puzzling since it isn't consistent with the figures on http://www.adaptall-2.com/lenses/20A.html Must be copy variation. Or corner measurements weren't done as extreme as you are showing here in the eighties.


PostPosted: Thu Apr 21, 2022 11:20 am    Post subject: Reply with quote
stevemark wrote:


I have included also the results of the Nikkor-P 2.5/105mm (later and better Xenotar type). Comparing these humble zooms with one of the most famous Nikkors may seem a bit daring - but look carefully at the images Wink



Well... the Minolta really outperforms the Nikkor! And I just bought one... should I just recycle it in the yellow bin? (just kidding).


PostPosted: Thu Apr 21, 2022 12:08 pm    Post subject: Reply with quote
Zamo wrote:
stevemark wrote:


I have included also the results of the Nikkor-P 2.5/105mm (later and better Xenotar type). Comparing these humble zooms with one of the most famous Nikkors may seem a bit daring - but look carefully at the images Wink



Well... the Minolta really outperforms the Nikkor! And I just bought one... should I just recycle it in the yellow bin? (just kidding).


Took this Minolta out last week, and it truly is an impressive lens. Compared it with my Topcor RE 100/2.8. As a portrait lens I find them equally good/ pleasing, as a landscape lens the MDiii is a bit better in the corners. Stopped down to f/8, the Topcor is very close though, which is quite amazing giving its age.

Bottom line: for landscape I prefer the Minolta, for portraits the Topcor (much better build qiality, smoothness of mechanics).


PostPosted: Sun Oct 02, 2022 12:22 pm    Post subject: Reply with quote
I appreciate the information. Do you need a dissertation writing service? And you want to learn it from a professional. Everyone wishes to produce the greatest essay possible for themselves. Do you want to write my dissertation for me? But you want your dissertation to stand out from the crowd; it is not a copied paragraph, but your own words. As a result, you can benefit from this connection. You must discover how to write a dissertation effectively here. So you may simply write on any subject.

Last edited by MaryannEllison on Tue Oct 04, 2022 4:10 pm; edited 1 time in total


PostPosted: Sun Oct 02, 2022 1:20 pm    Post subject: Reply with quote
caspert79 wrote:
Zamo wrote:
stevemark wrote:


I have included also the results of the Nikkor-P 2.5/105mm (later and better Xenotar type). Comparing these humble zooms with one of the most famous Nikkors may seem a bit daring - but look carefully at the images Wink



Well... the Minolta really outperforms the Nikkor! And I just bought one... should I just recycle it in the yellow bin? (just kidding).


Took this Minolta out last week, and it truly is an impressive lens. Compared it with my Topcor RE 100/2.8. As a portrait lens I find them equally good/ pleasing, as a landscape lens the MDiii is a bit better in the corners. Stopped down to f/8, the Topcor is very close though, which is quite amazing giving its age.

Bottom line: for landscape I prefer the Minolta, for portraits the Topcor (much better build qiality, smoothness of mechanics).


Woops, I think I created some confusion here. I compared the Minolta MD3 100/2.5 with the Topcor RE 100/2.8, not the MD 75-150/4. However, I have the 75-150/4 as well and I find its real life output very impressive.


PostPosted: Mon Oct 03, 2022 7:55 am    Post subject: Reply with quote
Had the Minolta MD 75-150 for a while and loved it.

Then I bought the Contax-Zeiss 80-200 and the Minolta collected dust...

So I sold the Minolta, because I am a lens user, not a collector.

Then I bought the Contax-Zeiss 100-300 which left both the 80-200 and the 75-150 in the dust.

But it is heavy... so I looked on Ebay for another copy of the Minolta 75-150 for opportunities where I want to pack light / compact.

I had luck: From a French seller I got a virtually flawless copy, even better than the first one.

While the Contax-Zeiss 100-300 delivers such special, perfect image quality, the Minolta is not THAT much behind, has is own charming colors & rendering and is simply fun to have on a hike.


PostPosted: Fri Oct 07, 2022 11:42 pm    Post subject: Reply with quote
stevemark wrote:
Here's the first part of the test - those six lenses mentioned above at their shortest focal length (70mm or 75mm).

As usual these are 100% crops from the corners of 24 MP FF JPGs out of the Sony A7II.

PLEASE CLICK TWICE ON THE IMAGE TO GET THE FULL RESOLUTION!

(...)

I'm a bit puzzled about the Olympus. Is there a common failure mode for these lenses, e. g. a plastic part in the zoom mechanism that fails (bearings, maybe)? While Olumpus MF gear is not common here in Switzerland, the Oly 75-150mm is readily available at any time, usually in several samples, on local online auction platforms. Canon and Nikon are rarer, and Minolta / Konica can't be found easily. This suggests that the Oly isn't really a keeper ...

Results at f=100mm and f=150mm will follow tomorrow.

S


Oh dear Stevemark, your tests are just what I need to focus my purchases!!

It went almost exactly as I expected. I expected the Minolta to be the best, followed by Canon FD and Nikon, then Konica, then Olympus, while the Mamiya was going to be a question mark (sometimes they surprise).

The surprise was that the Nikon Series E wasn't as great as it is often touted by the Nikonians. Good but not fabulous, maybe due to the faster aperture.

The Olympus I expected it to be not as good as the rest (sorry, I think Zuikos in general are overrated), however this one must have some mechanical problem.

The very interesting thing, and I think it hasn't been mentioned, is that the Canon FD 75-150, contrary to the Nikon lens and probably most of the others, is an optically compensated zoom, like the earliest zooms like the Zoomar 36-82, Pan-Cinor, etc. Most zooms are mechanically compensated zooms.

This is an older way to design a zoom, however it has the advantage of being mechanically more resilient, easier to keep the mechaniical precision good, since it doesn't require zoom cams, sleeve bushings, etc.

Canon's is probably one of the last optically-compensated zooms to be designed, since the design is from the late 70s (new FD line was introduced 1979).


PostPosted: Sat Oct 08, 2022 12:01 am    Post subject: Reply with quote
stevemark wrote:
The Oly 75-150 is a much older design than, say, the corresponding Minolta and the Canon zooms. And besides this: The (much hyped) Olympus 3.5/21mm, for instance, certainly is the worst of my many OEM superwides. Olympus obviously did make compromises when designing their lenses. Small size and high performance are very difficult to achieve simultaneously ...


You and I are on the same page then. I have to put my bulletproof vest on when I criticize OM Zuikos because the Olympus fans get enraged, they think they have the ultimate lens system.

It's true that compactness comes with a cost, and this already is known by Pentaxians, some Pentax-M lenses, while being perfectly good, are not as good performing as their prior Pentax-K equivalents, even considering that some of those Pentax-K are older designs, some times incredibly old (!)

Now, a separate observation:

Considering http://forum.mflenses.com/userpix/20166/7252_75150_5_1.jpg this table:

The number of groups a lens has can give you a measure of which one could be lower in contrast. Few groups give potentially high contrasts. Of course, this is not a hard rule since a lens with, say, 7 groups could be optimized for higher contrasts while a lens with, 5 groups could perhaps be optimized for other parameters giving slightly less contrast.

The minolta, the most contrasty out there, has the least amount of groups, 8.

But it's interesting that the Zuiko has a 15/11 (11 groups) structure, while the Hexanon a 15/12 structure. Yet the Hexanon shows much better contrast. That Zuiko has probably single coatings or not very good coatings.

I woudln't be surprised, the OM lenses were among the last ones to get multicoating in the 70s.


PostPosted: Mon Oct 10, 2022 9:12 pm    Post subject: Reply with quote
flavio81 wrote:

The surprise was that the Nikon Series E wasn't as great as it is often touted by the Nikonians. Good but not fabulous, maybe due to the faster aperture.

The Nikon 3.5/75-150 renders a bit softer (lower contrast) than e. g. the Minolta, but it is smaller and about 1 EV faster than the Canon nFD! I would recommend the Nikkor for portrait, the Minolta and the Canon for landscapes.

flavio81 wrote:
The Olympus I expected it to be not as good as the rest (sorry, I think Zuikos in general are overrated), however this one must have some mechanical problem.

It's a bit a mystery to me, as I said above. I have two copies of the Olympus (a earlier "silver nose" and a later "black nose"), and both are performing pretty badly. That said, the Oly is an early zoom, and e. g. the Minolta 3.5/80-160mm (a huge monster zoom from the early 1960s) is as bad as the Olympus 4/75-150mm.

flavio81 wrote:
The very interesting thing, and I think it hasn't been mentioned, is that the Canon FD 75-150, contrary to the Nikon lens and probably most of the others, is an optically compensated zoom, like the earliest zooms like the Zoomar 36-82, Pan-Cinor, etc. Most zooms are mechanically compensated zooms.

This is an older way to design a zoom, however it has the advantage of being mechanically more resilient, easier to keep the mechaniical precision good, since it doesn't require zoom cams, sleeve bushings, etc.

Yep, true - same principle as the FD/nFD 5.6/100-200mm or the Minolta MC/MD 5.6/100-200mm. And probably also the MinAF 4.5/100-200mm. However the nFD 4.5/70-150mm is really prone to fungus: I have three samples here with fungus, all from the waste bin of a local photo store ...!

S


PostPosted: Tue Oct 11, 2022 2:36 pm    Post subject: Reply with quote
stevemark wrote:

Yep, true - same principle as the FD/nFD 5.6/100-200mm or the Minolta MC/MD 5.6/100-200mm. And probably also the MinAF 4.5/100-200mm. However the nFD 4.5/70-150mm is really prone to fungus: I have three samples here with fungus, all from the waste bin of a local photo store ...!

S


85% of the Canon lenses of that era I've had in my hands suffered from one serious thing or the other to be honest. It's a pity because many of their lenses had great optics.


PostPosted: Tue Oct 11, 2022 4:03 pm    Post subject: Reply with quote
caspert79 wrote:

It's a pity because many of their lenses had great optics.


It really is ...!!

S


PostPosted: Wed Oct 12, 2022 4:06 am    Post subject: Reply with quote
I have bought a number of Minolta, Contax, Pentax and Olympus lenses in the last few years. Some had optical misalignments (most probably that's why their owners put them on Ebay...), but all of them had good to great bulid quality, and none had problems like fungus.

Seems like Canon lenses were the worst of all from the overall quality standpoint? I see that they are not very popular in the vintage lens community anyway compared to other brands...


PostPosted: Wed Oct 12, 2022 8:46 am    Post subject: Reply with quote
hasenbein wrote:
I have bought a number of Minolta, Contax, Pentax and Olympus lenses in the last few years. Some had optical misalignments (most probably that's why their owners put them on Ebay...), but all of them had good to great bulid quality, and none had problems like fungus.

Seems like Canon lenses were the worst of all from the overall quality standpoint? I see that they are not very popular in the vintage lens community anyway compared to other brands...


Well, that's relative to say, as 85mm and 50mm 1.4 are high desired lenses anytime, not even mentioned higher class L.
I do have 2 of the 135 mm nFD 2.8 , probably some of the lightest 135 around both suffering from haze and fungus front group . The 28mm is delivering some nice shots also, but it's still true that nFD suffer some serious issues related cheap materials (less the FD as I know) . In the past 7 years I've only seen a 85mm nFD on sale locally ,and that one had haze also.


PostPosted: Wed Oct 12, 2022 9:35 am    Post subject: Reply with quote
hasenbein wrote:


Seems like Canon lenses were the worst of all from the overall quality standpoint? I see that they are not very popular in the vintage lens community anyway compared to other brands...


After using Pentax cameras und lenses, I switched to a Canon FD system in the early 1990s and used it professionnally (portraits, fashion, travel) up to the end of the 1990s when I switched to the Canon AF system. At the time i've been very happy with the ruggedness and optical performance of my Canon FD lenses (a part from some Tamron SP lenses, I had FD 24 mm f/2,8 SSC, FD 35 mm f/2 SSC and nFD 85 mm f/1,8 lenses.

A few years ago, realising the low prices of most Canon FD lenses, I bought several dozen lenses of that system and still I'm very satisfied with the optical performance and mechanical relability. Statistically (i still have about fourty FL, FD and nFD samples) i've found that they are not more prone to fungus than other lenses and when infected, the SC and SSC coatings don't give in to the attacks - with Zuiko lenses, for example, i've already had several cases with lens surfaces attacked and destroyed by fungus.

The Canon FD mount was and is considered by many as being grossly overengineered. While it is certainly true that the mechanism is not easy to understand, it is nethertheless very reliable - cases of chrome ring lenses "falling off" only happen with ignorant users and damaged aperture mechanisms mostly occur when less knowledgeable persons tamper with it by forcing the levers. I only see one potential pitfall when buying FD lenses : if not serviced properly, all twin-ring zooms and fixed fovcal lenses with floating elements or interior focusing groups will fail due to rotten slider bearings. So never buy one of these lenses unless integrating service costs or being able to repair them yourselves. Apart from that, you frequently find overblown negative judgments by otherwise competent users: a professor from Kentucky constantly brings up a supposedly big issue with a stamped metal part in the back of nFD lenses - according to him, this part (exchangeable within 15 seconds...) frequently gets mangled and deformed whereas this part only gets damaged when using brute force removing the lever mechanism at the back. Another one claims that Canon FD lenses introduce an strong orange color cast which is utter bullshit, given that those lenses distinguish themselves by a perfectly neutral color rendering which is unform throughout all the range (i'm very picky about color management and color profile my camera bodies myself...).

So i would conclude that most claims about the bad quality of the FD line are based on bad experiences with some isolated samples (i've already said it, i've got more than fourty and resold about the same number...) which are not statisticallty relevant Wink


PostPosted: Wed Oct 12, 2022 2:54 pm    Post subject: Reply with quote
Alsatian2017 wrote:
hasenbein wrote:


Seems like Canon lenses were the worst of all from the overall quality standpoint? I see that they are not very popular in the vintage lens community anyway compared to other brands...


After using Pentax cameras und lenses, I switched to a Canon FD system in the early 1990s and used it professionnally (portraits, fashion, travel) up to the end of the 1990s when I switched to the Canon AF system. At the time i've been very happy with the ruggedness and optical performance of my Canon FD lenses (a part from some Tamron SP lenses, I had FD 24 mm f/2,8 SSC, FD 35 mm f/2 SSC and nFD 85 mm f/1,8 lenses.


Around 1985 - when I was 16 y old and planning to buy my first professional camera - both the Canon New F-1 and the Leica M6 were at the top of the list. The Leica obviously had really nice lenses, but the M6 itself was a bit limited for my kind of work. The New F-1 did look perfect, and the lenses available were outstanding. At the time, no one else had a rectilinear 2.8/14mm, a 1.4/24mm, an aspherical normal lens, a 1.2/85mm, a 2.8/400mm ... you name it. Which means I still have a weakness especially for the New F-1 and the nFD lenses. That said, I did hesitate to buy into the Canon system back then; instead I did upgrade my Mamiya kit with a few nice lenses. And one year later, when the Minolta 9000 was introduced, i knew that this would be my system. I was right.

Alsatian2017 wrote:
A few years ago, realising the low prices of most Canon FD lenses, I bought several dozen lenses of that system

So did I - about 100 Canon MF lenses of 80 different types here right now.

Alsatian2017 wrote:
and still I'm very satisfied with the optical performance

Yep, true. Unless, however ... (see below)

Alsatian2017 wrote:
and mechanical relability.

No, I'm not, especially when it comes to the more expensive lenses! See below, again ...


Alsatian2017 wrote:
Statistically (i still have about fourty FL, FD and nFD samples) i've found that they are not more prone to fungus than other lenses and when infected, the SC and SSC coatings don't give in to the attacks - with Zuiko lenses, for example, i've already had several cases with lens surfaces attacked and destroyed by fungus.

Don't agree with that either. Probably >10% of my Canon MF lenses (and a similar number of MF Nikkors) have fungus and/or fogging (closely related). Compare that to only one Minolta MF lens with fungus and a second one with haze (out of 200 lenses = about 1%). There is, however, an early Minolta AF lens which often is fooged: the otherwise excellent "big beercan" 4.5-5.6/75-300mm.

Alsatian2017 wrote:
The Canon FD mount was and is considered by many as being grossly overengineered. While it is certainly true that the mechanism is not easy to understand, it is nethertheless very reliable - cases of chrome ring lenses "falling off" only happen with ignorant users and damaged aperture mechanisms mostly occur when less knowledgeable persons tamper with it by forcing the levers.

Absolutely agree - i never had troubles with the FD/nFD mount itself.

Alsatian2017 wrote:
I only see one potential pitfall when buying FD lenses : if not serviced properly, all twin-ring zooms and fixed fovcal lenses with floating elements or interior focusing groups will fail due to rotten slider bearings. So never buy one of these lenses unless integrating service costs or being able to repair them yourselves.

Yep, and that's a biggie. Quite a few of my FD/nFD lenses (usually those optical treasures) have this problem. My nFD 4/17mm and 2.8/20mm seem to be OK, the 2/24mm and the nFD 2/28mm have rotten bearings. The nFD 1.2/50mm L (absolutely new lens just out of the box) had a blocked aperture (no slider bearings here, thank goodness). The 1.2/85mm (also absolutely new out of the box) was OK. The nFD 4/200mm as well as the FD 2.8/300mm, the FD 4.5/400mm and the nFD 2.8/400mm all had rotten bearings. Same problem probably with my nFD 2.8/200 IF, my 4/80-200mm L and certainly with my two samples of the nFD 5.6/100-300mm L. And the 3.5/20-35mm L ...

Sure enough some people here were arguing that Canon had introduced a new technology here and therefore was prone to "early mistakes". Wrong. Slider bearings had been used for a long time in zooms, and even my oldest Minolta zooms from the mid-1960s (let alone the newer ones) have such problems. Canon simply chose the wrong material.

Alsatian2017 wrote:
Another one claims that Canon FD lenses introduce an strong orange color cast which is utter bullshit,

It certainly is.

Alsatian2017 wrote:
So i would conclude that most claims about the bad quality of the FD line are based on bad experiences with some isolated samples (i've already said it, i've got more than fourty and resold about the same number...) which are not statisticallty relevant Wink


So my sample and your sample do not completely agree Wink

S


PostPosted: Wed Oct 12, 2022 4:32 pm    Post subject: Reply with quote
Alsatian2017 wrote:
with Zuiko lenses, for example, i've already had several cases with lens surfaces attacked and destroyed by fungus.


I think one has to be careful as to the conclusions that can be drawn from this. Given the relatively common involved glass compositions, grinding & polishing operations and coating materials and processes involved, it would be difficult to argue that one manufacturer's lenses are/should be particularly more prone to fungal growth and/or damage than another manufacturer's lenses, especially where exterior non-cemented surfaces are involved.

Far more likely causes for any observed difference are both the environmental conditions and cleaning routines that the particular lenses have been exposed to over their lifetimes. Possibly some lenses have had more exposure to fungal spores simply because of where they may have been used. Others may have seen more dust build-up on the surface and have more dust buildup sitting in the crevice between the lens surface and lens retaining ring.

Fungal growth needs the right moisture condition (> ~70% RH), the right temperature range, and a food source. Dust and oil residues are the most likely food source, rarely the coatings themselves. Even when cleaned properly, oil residues and dust tends to still be present in the small crevice/corner where the lens surface meets the lens retaining ring, and it is no coincidence that the majority of fungal growth starts from this area and then radiates out from there.

Previous owners simply may have had different cleaning routines; not everyone pays the same attention to cleaning the area where the lens retaining ring meets the lens surface. This is a tricky area to clean anyway as it it also where the more gritty dust tends to accumulate which can cause scratches if cleaning is not done with enough care.

Trying to keep fungal spores away from the lens is a fool's errand; fungal spores are literally abundant everywhere in the air, and as soon as the lens leaves the dust-controlled manufacturing facility it will be covered in fungal spores all over. It is all about controlling moisture and eliminating a food source; i.e. keeping the lenses both dry and clean.


PostPosted: Wed Oct 12, 2022 5:20 pm    Post subject: Reply with quote
RokkorDoctor wrote:

I think one has to be careful as to the conclusions that can be drawn from this. Given the relatively common involved glass compositions, grinding & polishing operations and coating materials and processes involved, it would be difficult to argue that one manufacturer's lenses are/should be particularly more prone to fungal growth
...

Fungal growth needs the right moisture condition (> ~70% RH), the right temperature range, and a food source.


Different manufacturers obviously have been using a wide variety of greases, each grease traditionally consisting of

1) an (mineral) oil and
2) a soap (the soap being a salt of a fatty acid)

Commonly used metal ions for the salt of the fatty acid are Na+ and K+ (toilet soaps). When manufacturing greases, however, other metal ions usually are prefered, such as Ca2+, MG2+, Al3+ and especially Li+ are used. Leica, for instance, has used expensive Barium soaps for their greases - and I would expect them to be quite nasty (=toxic).

And from here we can see that some greases may very well aggressively attack a given coating, while another grease may be quite benign ...

So it's pretty clear that some greases are good food for fungi, and others probably not so much Wink


...

Trying to keep fungal spores away from the lens is a fool's errand; fungal spores are literally abundant everywhere in the air... It is all about controlling moisture and eliminating a food source; i.e. keeping the lenses both dry and clean.[/quote]

... or making the food (=grease) really toxic Wink

S


PostPosted: Wed Oct 12, 2022 5:39 pm    Post subject: Reply with quote
Alsatian2017 wrote:
if not serviced properly, all twin-ring zooms and fixed fovcal lenses with floating elements or interior focusing groups will fail due to rotten slider bearings. So never buy one of these lenses unless integrating service costs or being able to repair them yourselves. Apart from that, you frequently find overblown negative judgments by otherwise competent users: a professor from Kentucky constantly brings up a supposedly big issue with a stamped metal part in the back of nFD lenses - according to him, this part (exchangeable within 15 seconds...) frequently gets mangled and deformed whereas this part only gets damaged when using brute force removing the lever mechanism at the back. Another one claims that Canon FD lenses introduce an strong orange color cast which is utter bullshit, given that those lenses distinguish themselves by a perfectly neutral color rendering which is unform throughout all the range (i'm very picky about color management and color profile my camera bodies myself...).

So i would conclude that most claims about the bad quality of the FD line are based on bad experiences with some isolated samples (i've already said it, i've got more than fourty and resold about the same number...) which are not statisticallty relevant Wink


This. Well said.

The sliding bearings (rubber bushings) is a known problem, sadly eBay sellers and many buyers are oblivious about it. Moreover, many camera technicians are also oblivious to this.

This is NOT a consequence of bad build quality -- quite the opposite, Canon used rubber-on-top-of-brass for riding on zoom cams, instead of the nylon-over-metal strategy of other manufacturers. Canon's choice gives higher mechanical precision, however rubber will degrade after decades.

The New FD have been believed to have "inferior" quality but these things are true:

1. There are different qualities within the FDn line, a New FD 50/1.2 is clearly better built than a FDn 50/1.4 which in turn is clearly better built than a FDn 50/1.8.

2. All these lenses used special teflon-coated helicoids which are almost eternal, i've yet to find a New FD lens with focusing helicoid problems, while i've found tons of Nikon AI and pre-AI lenses with helicoid problems.

3. Most FDn lenses that appear to use "plastic" use in fact a very strong fiberglass composite, a great material which also has the same index of contraction-expansion as glass, so in some sense is a better material than classic metals.

4. The FD mount is the only mechanical mount that allows the camera to control the aperture value with a big degree of precision, simply due to the far bigger angle of movement allocated to this operation, compared to the Nikon AI-S and Pentax K mounts where they use the kludge of employing the same lever used for closing the diaphragm as the one to set the aperture.

I have read that Canon's R&D budget has always being way bigger than Nikon's (and other manufacturers) simply because of being a far bigger company. Anybody could rest assured the New FDs were to be an improvement over earlier FD lenses.


PostPosted: Wed Oct 12, 2022 5:44 pm    Post subject: Reply with quote
RokkorDoctor wrote:
Trying to keep fungal spores away from the lens is a fool's errand; fungal spores are literally abundant everywhere in the air, and as soon as the lens leaves the dust-controlled manufacturing facility it will be covered in fungal spores all over. It is all about controlling moisture and eliminating a food source; i.e. keeping the lenses both dry and clean.


Correct.

I own more than 60 lenses, from many brands: Canon FD, EF, Nikon pre-AI, AI, AI-S, Pentax K, M, M42, Bronica ETR, Pentax 6x7, Zeiss-Opton, Arsenal, etc.

All of them were bought clean of fungi or were cleaned by me after purchase.

Years have passed and none has had any fungal growth. This is because they sit on a room with controlled humidity, never greater than 65%. I use a dehumidiifer.


PostPosted: Wed Oct 12, 2022 7:52 pm    Post subject: Reply with quote
stevemark wrote:

Different manufacturers obviously have been using a wide variety of greases, each grease traditionally consisting of

1) an (mineral) oil and
2) a soap (the soap being a salt of a fatty acid)


... and often a dry-lube additive ...

stevemark wrote:

Commonly used metal ions for the salt of the fatty acid are Na+ and K+ (toilet soaps). When manufacturing greases, however, other metal ions usually are prefered, such as Ca2+, MG2+, Al3+ and especially Li+ are used. Leica, for instance, has used expensive Barium soaps for their greases - and I would expect them to be quite nasty (=toxic).


Yes, lithium stearate is a very often used soap thickener (and molybdenum disulfide used to be an often used dry-lube in lens grease, as any lens-repair-enthusiast with a white sofa will find out soon enough Wink ). Non-soap thickener greases do also exist however; e.g. greases based on a polyurea thickener are also fairly common, but I have not heard of that being used in lenses (or cameras). Older greases often had a mix of organic base oils, some of which with more volatile fractions and when that spreads through the lens that could definitely promote fungal growth. So yes; older lenses with poorer quality organic base-oil greases could definitely be more susceptible to fungal damage.

stevemark wrote:
... or making the food (=grease) really toxic Wink
S


Whilst I understand the idea of a toxic grease you suggest, I'm not really sure how useful a toxic soap thickener would be in reducing fungal growth though; usually the soap thickener stays in place (in the helicoid), but it is the lighter oil fractions (organic oils), or even the synthetic oil (less problematic) that will evaporate and condensate back into the capillary gaps. Thus the oil often found underneath the lens retaining rings and between the elements and cell mount would be largely if not totally free from the toxic thickener contained in the grease they evaporated/migrated from. If the fungus spread far enough that it would reach the toxic helicoid grease inside the lens, it could be killed off but by then I would expect the damage likely to be beyond repair anyway.
Post new topic   Reply to topic
Home   Manual Focus Lenses
Goto page Previous  1, 2, 3, 4, 5
Page 5 of 5