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What's the latest lens you added to your collection?
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PostPosted: Wed May 08, 2019 8:03 pm    Post subject: Reply with quote

Sciolist wrote:
One of the things I've noticed is that the tint appears to decay in half lifes when attacked with UV, i.e It takes as long to reduce the initial tint by half, as it does to reduce what's left by half,... and on and on. The process seems to be one of diminishing returns. Have you noticed that with your process?


In most cases yes, but not all. Like I said, my Auto Yashinon DX 50 1.4 - the old version with the chrome barrel - cleared up completely as if by magic. Some of them do take longer and the last 30% of the tint seems to take a lot longer to get rid of than the first 70% did. If I get one mostly clear I usually haven't bothered trying to keep going until it's perfect. I'm no expert in these things, but I assume it must have something to do with the different compound mixtures used by different manufacturers.

My Super Takumar 50 1.4 definitely has a yellow-brown coating on the front element that disguises the tint. I think you can tell the difference if you examine it closely though.

The Pancolar appears to be uncoated, so the tint is easy to see. It'll hit 48 hours tonight so I'll look at it then and judge the progress.


PostPosted: Wed May 08, 2019 10:15 pm    Post subject: Reply with quote

KEO wrote:

My Super Takumar 50 1.4 definitely has a yellow-brown coating on the front element that disguises the tint. I think you can tell the difference if you examine it closely though.

The Pancolar appears to be uncoated, so the tint is easy to see. It'll hit 48 hours tonight so I'll look at it then and judge the progress.



As I mentioned earlier, I am using a Tak 55 1.8 to compare by holding them both over a sheet of white paper. Doing this, I've watched the browning recede, but I still have a little way to go to completely clear it. It currently provides a brown speckling when held over the paper and looked through.


H.G Deitz of the University of Kentucky notes that the browning, or 'yellowing' as he refers to it, blunts the Takumar's sharpness. He says no more than that in the link below. I wonder if it is particular to the Takumar, or if it is a particular consequence of the development of Farbe centers in optical glass. If it is the latter, you may be able to notice an increase in sharpness in your Pancolar if you shot anything beforehand. With my 1.4, and after reading the hyperbole, I was disappointed with the level of sharpness I was getting from my heavily browned lens (the worst I've personally seen), but sods law, I didn't save any shots from it in that state.


See under "Normal Lenses" -

http://aggregate.org/DIT/MYLENSES/


PostPosted: Thu May 09, 2019 12:31 pm    Post subject: Reply with quote

KEO wrote:
...

I use a cheap UV bug lamp. Results have varied from lens to lens, which seems a bit odd.

My Auto Yashinon DX 50mm 1.4 cleared up completely after about 48 hours, even though it was pretty dark to begin with. Others took a bit longer. My Auto Mamiya 55 1.4 didn't seem to clear at all. It makes me wonder whether some of the color isn't from coatings rather than thorium.

The Pancolar has cleared a fair amount after only about 20 hours, but it still has a good way to go. I'll give it a look again when it hits 48 hours.


The results depend on the position of the thoriated lens element.

1) Optical glass has a low transmission for UV
2) if the thoriated (yellowish) element is right in front, the UV light can reach it easily, and the glass "heals" easily
3) if the thoriated element is somwhere deep inside, curing it is more difficult or sometimes nearly impossible - unless one opens the barrel to expose the thoriated element directly to UV light

Stephan


PostPosted: Thu May 09, 2019 12:40 pm    Post subject: Reply with quote

[quote="Sciolist"]
KEO wrote:

My Super Takumar 50 1.4 definitely has a yellow-brown coating on the front element that disguises the tint.
...
With my 1.4, and after reading the hyperbole, I was disappointed with the level of sharpness I was getting from my heavily browned lens (the worst I've personally seen), but sods law, I didn't save any shots from it in that state.


The early Pentax 1.4/50mm lenses from the 1960s and 1970s are visibly inferior to more modern 1.4/50 constructions.
The construction of a fast (f1.4) 50mm lens with enough backfocus (distance between last glass element and film) was very difficult in the early 1960s. Details about Nikons struggle to get such a lens can be read in the corresponding Nikkor tales.

Look at this comparison between the Pentax 1.4/50mm and the Topcor RE 1.8/55mm - the latter being sligtly slower and slightly longer (backfocus!!):

TO REALLY SEE THE DIFFERENCES LOOK AT THE IMAGE AT 100% BY CLICKING IT TWICE!



Stephan


PostPosted: Thu May 09, 2019 3:03 pm    Post subject: Reply with quote

Well been a bit busy moving and whatnot and I'd probably take up a page with the stuff I've got recently but todays post was definitely a winner.

Got a job lot of a couple of knackered Exa II's, a Praktica Nova along with an Exa mount Lydith, a sparkling Helios 44-2 and this:



Given I paid less than the going rate for the Helios for the lot you could say I'm quite pleased... Very Happy


PostPosted: Thu May 09, 2019 8:02 pm    Post subject: Reply with quote

Like 1


PostPosted: Fri May 10, 2019 8:35 am    Post subject: Reply with quote

stevemark wrote:


The results depend on the position of the thoriated lens element.

1) Optical glass has a low transmission for UV
2) if the thoriated (yellowish) element is right in front, the UV light can reach it easily, and the glass "heals" easily
3) if the thoriated element is somwhere deep inside, curing it is more difficult or sometimes nearly impossible - unless one opens the barrel to expose the thoriated element directly to UV light

Stephan



It's good to have someone else confirm it. Having discovered (it shouldn't have been a surprise) that lenses have 'laser' like abilities when allowed to concentrate sunlight, I worked through that it would make little difference if I just faced the rear of the lens to the sky (see below), the thoriated elements being to the rear of the diaphragm anyway. It avoided the chance of the house burning down!


And thanks for taking the time to post up those test comparisons. It's much appreciated.



Last edited by Sciolist on Fri May 10, 2019 9:19 am; edited 1 time in total


PostPosted: Fri May 10, 2019 8:49 am    Post subject: Reply with quote

Sciolist wrote:
stevemark wrote:


The results depend on the position of the thoriated lens element.

1) Optical glass has a low transmission for UV
2) if the thoriated (yellowish) element is right in front, the UV light can reach it easily, and the glass "heals" easily
3) if the thoriated element is somwhere deep inside, curing it is more difficult or sometimes nearly impossible - unless one opens the barrel to expose the thoriated element directly to UV light

Stephan



It's good to have someone else confirm it. Having discovered (it shouldn't have been a surprise) that lenses have 'laser' like abilities when allowed to concentrate sunlight, I worked through that it would make little difference if I just faced the rear of the lens to the sky, the thoriated elements being to the rear of the diaphragm anyway. It avoided the chance of the house burning down!


And thanks for taking the time to post up those test comparisons. It's much appreciated.


So how does the output from the lens when treated compare to shot as is then with white balance corrected? Not had the time to try this with the Pancolars I've got and instead I've just shifted the WB to compensate for the warmth...


PostPosted: Fri May 10, 2019 8:57 am    Post subject: Reply with quote

Going back to my last purchase post, just discovered upon closer inspection the Helios 44-2 is actually a Valdai model, so rather than start an umpteenth thread on these things - does anyone know of any discernible differences between those produced by Valdai compared to KMZ?

I figure I'm also going to keep the Exa Lydith and sell my M42 version as the rear flange doesn't retract beyond the mount unlike the M42 so it'll be far better to use on my EOS.. Very Happy


PostPosted: Fri May 10, 2019 9:02 am    Post subject: Reply with quote

Gott23 wrote:

So how does the output from the lens when treated compare to shot as is then with white balance corrected? Not had the time to try this with the Pancolars I've got and instead I've just shifted the WB to compensate for the warmth...



I've not tried it yet Gott, but I suppose I'll soon find out. I'm also interested to see if there is any increase in sharpness (see post above with link).


PostPosted: Fri May 10, 2019 1:30 pm    Post subject: Reply with quote

Gott23 wrote:
Going back to my last purchase post, just discovered upon closer inspection the Helios 44-2 is actually a Valdai model, so rather than start an umpteenth thread on these things - does anyone know of any discernible differences between those produced by Valdai compared to KMZ?


You mean apart from the logo?
http://cameras.alfredklomp.com/logos/


PostPosted: Fri May 10, 2019 1:30 pm    Post subject: Reply with quote

The latest one I've received is a Voigtlander 50mm/3.5 Skopar. Yet to be adapted,
It's come out of a damaged Vito I folding camera (film interlock jammed) if I can sort out the camera I might put it back in after testing it on my digital cameras of course.


PostPosted: Fri May 10, 2019 2:16 pm    Post subject: Reply with quote

Gott23 wrote:

So how does the output from the lens when treated compare to shot as is then with white balance corrected? Not had the time to try this with the Pancolars I've got and instead I've just shifted the WB to compensate for the warmth...


If i calibrate the camera using a "Kodak grey card" and the built-in calibration process of A7/A7II on a thoriated lens (yellow tint) and another non-thoriated lens (normal colors), the "average grey" of the Kodak grey card looks identical.
Colors in real life, however, look different. I have tried and researched this extensively with my Biotar 7.5cm 1:1.5 which has quite some yellow/brownish color cast as well.

Stephan


PostPosted: Sat May 11, 2019 7:10 pm    Post subject: Reply with quote

stevemark wrote:

The results depend on the position of the thoriated lens element.

1) Optical glass has a low transmission for UV
2) if the thoriated (yellowish) element is right in front, the UV light can reach it easily, and the glass "heals" easily
3) if the thoriated element is somwhere deep inside, curing it is more difficult or sometimes nearly impossible - unless one opens the barrel to expose the thoriated element directly to UV light


Because of this thread I did an inspection of my seven thorium lenses. 48 hours of UV exposure from my bug light cleared four of them 95% or better. Only the 50mm Takumar 1.4, which has a pale golden coating on both the front and rear elements, and the 55mm Mamiya/Sekor 1.4, which has an amber coating on both the front and rear elements. I don't think the coating is responsible though, except that it disguises the tint unless you hold the lens up to a window or a light source, in which case the tint is easy to see. It's possible I simply gave up on clearing these two completely out of haste, because...

I put both back under the bug lamp with the Pancolar and the Mamiya cleared up completely with an overnight exposure. The Takumar is taking longer, but it's getting better so I'll leave it for the time being.

The Pancolar, which was pretty dark when I got it, has cleared up about 80-85% so far, though this has taken several days. I was impatient to try it out so I went shooting with it once and used white balance to compensate for the tint, but it still required some de-yellowing in post to make the shots look right. I'm leaving it under the lamp to see how long it'll take to clear it completely. It's still getting better, but slowly. Opening it up to expose the thoriated elements to the UV is an interesting idea, but I don't think it will be necessary.

BTW, I sometimes place my lenses with the rear element toward the lamp, but usually I set the rear end on a plexiglass mirror and let the UV pour in through the front.

A list of lenses I didn't have any trouble de-yellowing:

50mm Yashinon-DX 1.4
55mm SMC Takumar 1.8
55mm Auto Rikenon 1.4
55mm Auto Rikenon 1.4


PostPosted: Sat May 11, 2019 7:13 pm    Post subject: Reply with quote

I just picked up a NOS Kodak Aero Ektar 178mm f/2.5. It's got little to no discoloration and is in cracking condition. I'm looking to adapt it to my Fuji GFX-50r so any help in that regard would be great.

I got a threaded adapter that brings it down to M65 so now I'm considering an M65 to M65 helicoid and an M65 to GFX adapter to finish it off. The M65 to GFX adapter is 1mm thick, but I'm struggling to find the proper sized helicoid to attach to it. ANy ideas?


PostPosted: Sat May 11, 2019 10:01 pm    Post subject: Reply with quote

Not so much new in the post but the adapter was.. Very Happy



Now, does anyone have any idea what kind of filter I'm looking to get for this???? o.0

I figure it's a custom one given the shape of the thread on it and feck knows the size.. can't find much if any data on it on the usual places...

Luckily the Schnieder Xenar 135/f4 takes a standard 58mm filter but both obviously have their own rear caps if at all, but I definitely need to get something on the front of the Eurygon..


PostPosted: Sun May 12, 2019 10:40 am    Post subject: Reply with quote

I'll introduce two lenses with one shot:



Olympus OM-System Zuiko MC Auto-1:1 Macro 80mm F4
Minolta MC Rokkor-PF 55mm F1.7


PostPosted: Sun May 12, 2019 10:50 am    Post subject: Reply with quote

aidaho wrote:
I'll introduce two lenses with one shot:




Stunning Like 1 .


PostPosted: Sun May 12, 2019 11:01 am    Post subject: Reply with quote

Been shoppin'...



In order of focal length -

Hoya Super EL 40/3.5 (6/4)
Schneider-Kreuznach Componon - S 50/2.8 (6/4)
Minolta E.Rokkor 75/4.5 (4/3 - apparently)
Schneider-Kreuznach Durst Componon 80/5.6 (6/4)


25mm to 39mm adaptor
39mm to 42mm adaptor
42mm to Fujifilm FX adapter


Set of Pentax M42 Extension rings. (I already had these, but they are excellent at stopping things rolling away).


Well, that's the good news.


The bad news? The damn focusing helicoid is on a slow boat from China. 3 weeks now, but it's not like I didn't expect that. I'm just champing at the bit to use my new toys!


PostPosted: Sun May 12, 2019 6:47 pm    Post subject: Reply with quote

I just found another exemplar of the Leica Elmarit-R 28. For me it is a very special treasure because I got this 40 year old lens in as new condition including it`s original packing....


#1


#2


#3


PostPosted: Sun May 12, 2019 7:02 pm    Post subject: Reply with quote

After a long bidding fight i won this set of Mamiya SX lenses (image taken by the seller):



Among them probably the 2.8/35mm (or the 2.8/28mm??), certainly the 3.5/200mm and the 2.8/135mm, and obviously the very rare Mamiya Sekor SX 1.7/85mm. The latter is of particular interest, since it is the only ever Mamiya 1.7/85mm. There's nearly no information aboout it; even the three most important websites for Mamyia 35mm stuff (Ron Herron, Roland Stauber and Jörg Mück), only Ron Herron lists the lens (the others don't even mention it). And Ron Herron doesn't give any further information as well ...

And on mflenses there seems to be nothing ... only a few words about the SX 2.8/85mm!

I'll get the stuff tomorrow (along with a couple of nice MD lenses) and report later on!

Stephan


PostPosted: Sun May 12, 2019 7:38 pm    Post subject: Reply with quote

stevemark wrote:
KEO wrote:
...

I use a cheap UV bug lamp. Results have varied from lens to lens, which seems a bit odd.

My Auto Yashinon DX 50mm 1.4 cleared up completely after about 48 hours, even though it was pretty dark to begin with. Others took a bit longer. My Auto Mamiya 55 1.4 didn't seem to clear at all. It makes me wonder whether some of the color isn't from coatings rather than thorium.

The Pancolar has cleared a fair amount after only about 20 hours, but it still has a good way to go. I'll give it a look again when it hits 48 hours.


The results depend on the position of the thoriated lens element.

1) Optical glass has a low transmission for UV
2) if the thoriated (yellowish) element is right in front, the UV light can reach it easily, and the glass "heals" easily
3) if the thoriated element is somwhere deep inside, curing it is more difficult or sometimes nearly impossible - unless one opens the barrel to expose the thoriated element directly to UV light

Stephan


The UV requirement remains unproven. There are reports of clearing using light sourcr with no UV such as LED.


PostPosted: Sun May 12, 2019 7:46 pm    Post subject: Reply with quote

stevemark wrote:
After a long bidding fight i won this set of Mamiya SX lenses (image taken by the seller):


Among them probably the 2.8/35mm (or the 2.8/28mm??), certainly the 3.5/200mm and the 2.8/135mm, and obviously the very rare Mamiya Sekor SX 1.7/85mm. The latter is of particular interest, since it is the only ever Mamiya 1.7/85mm. There's nearly no information aboout it; even the three most important websites for Mamyia 35mm stuff (Ron Herron, Roland Stauber and Jörg Mück), only Ron Herron lists the lens (the others don't even mention it). And Ron Herron doesn't give any further information as well ...

And on mflenses there seems to be nothing ... only a few words about the SX 2.8/85mm!

I'll get the stuff tomorrow (along with a couple of nice MD lenses) and report later on!

Stephan


smk2 -> it's you!!! Shocked

I was hoping nobody saw the 85mm and possibly confused it with a 50/55mm 1.7 and keep the price low of the auction...

well now I know it's you, I don't mind I bidded too low haha

keep us informed then!


PostPosted: Sun May 12, 2019 8:42 pm    Post subject: Reply with quote

visualopsins wrote:
stevemark wrote:
KEO wrote:
...

I use a cheap UV bug lamp. Results have varied from lens to lens, which seems a bit odd.

My Auto Yashinon DX 50mm 1.4 cleared up completely after about 48 hours, even though it was pretty dark to begin with. Others took a bit longer. My Auto Mamiya 55 1.4 didn't seem to clear at all. It makes me wonder whether some of the color isn't from coatings rather than thorium.

The Pancolar has cleared a fair amount after only about 20 hours, but it still has a good way to go. I'll give it a look again when it hits 48 hours.


The results depend on the position of the thoriated lens element.

1) Optical glass has a low transmission for UV
2) if the thoriated (yellowish) element is right in front, the UV light can reach it easily, and the glass "heals" easily
3) if the thoriated element is somwhere deep inside, curing it is more difficult or sometimes nearly impossible - unless one opens the barrel to expose the thoriated element directly to UV light

Stephan


The UV requirement remains unproven. There are reports of clearing using light sourcr with no UV such as LED.


The energy of photons is inversely proportional to the wavelength, so UV is more energetic than visual...
It seems there may be blue wavelengths that are energetic enough to initiate the clearing reaction. (Unless the LED lights do give of some UV - white LEDs often have phosphours that are excited by the actual LED & emit light at longer wavelength - this gives a wider spectrum than purely mixing RGB LEDS)


PostPosted: Sun May 12, 2019 9:39 pm    Post subject: Reply with quote

DConvert wrote:
... (Unless the LED lights do give of some UV - white LEDs often have phosphours that are excited by the actual LED & emit light at longer wavelength - this gives a wider spectrum than purely mixing RGB LEDS)



I thought all L.E.D lights emit UV. From 'next to nothing', to sufficient enough to be used as UV flashlights (Blacklights). As you mention, it depends on what material is being used to produce the light.