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Must do, before using manual lens
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PostPosted: Fri Apr 11, 2014 8:48 am    Post subject: Must do, before using manual lens Reply with quote

I was inspired by this topic: http://forum.mflenses.com/lenses-facts-and-fallacies-part-ii-t65585.html

Newbie or even experienced users many times forget basics when using manual lens thus the results are far from optimal. So here what i had in mind:

1. Use hood (as long as possible until vignette occurs; don't be fancy - you can improvise using black matte paper)

2. Make rear lens baffle (mask) according to your sensor size: reduces stray light and flare (lens was not made for small sensors so you're not "cheating").
It does wonders. The idea even made it to Google patents: http://www.google.com/patents/US8000598

Again, you can improvise using black matte paper.

Photo from tutorial here: http://gfsnt.no/hexanon/

3. Check if your adapter is glossy inside. Many cheaper adapters are. Mine were all chrome.
Paint adapter's interior black matte color to reduce internal reflections.

4. Check lens internally. if you have not done it yet, have a courage to look through the lens under different angles and using strong light.
Obvious haze, dust or separation reduce contrast by some degree no matter what they told you. Perhaps some lens servicemen went out of business too fast.

5. Experiment with FILTERS and find those that improve image quality. Many photographers reports successful combinations.
Filters are cheap why not give them a try.


Last edited by Pancolart on Sat May 09, 2015 7:54 am; edited 1 time in total


PostPosted: Fri Apr 11, 2014 8:54 am    Post subject: Reply with quote

Never had an adapter that wasn't matte inside. Don't see the need for a baffle and very few of my lenses need a hood as long as I am not pointing them at the sun. Old zooms suffer from ghosting and flare, primes not really, especially if your technique is correct.


PostPosted: Fri Apr 11, 2014 11:59 am    Post subject: Reply with quote

I've had two adapters with glossy black interiors . . . both wreaked havoc with images. One was a cheap Chinese one, the other a far from cheap UK made one. As for lens hoods - they also keep the raindrops off the front element Wink More seriously, on the crop-format Leica M8 I can - and do - use the Leitz 90mm hood on my 50mm Summicron. It certainly makes a difference when a strong light source is just outside the field of view.

I'd never thought of adding a baffle Given my ham-handedness it's probably a non-starter for me but I can see the sense in the idea, especially if a lens has any potentially light-scattering surfaces inside it. As the old lady famously said, 'Every little helps'.


PostPosted: Fri Apr 11, 2014 12:27 pm    Post subject: Reply with quote

Just like hoods and baffles, you can add tripod and remote release to the list of things that can improve your pictures, though not every situation will require them, they do help in tougher situations.


PostPosted: Fri Apr 11, 2014 12:47 pm    Post subject: Reply with quote

I'm not saying these things are not of use for some lenses in some situations, but in no way do I agree they are a 'must do'.


PostPosted: Fri Apr 11, 2014 2:03 pm    Post subject: Reply with quote

Allow me to comment:

ad 1)
Yes, indeed. I almost always use a hood. Not only for IQ but also for protection.

ad 2)
Never have used one and I don't think I ever will.

ad 3)
Most of my adapters are black anyway. If you use silver ones intensely reflecting light, this will most probably have a deteriorating influence on IQ.

ad 4)
A covering layer of dust or a completely hazed lens will influence performce.
Some specks of dust, tiny scratches, some cleaning marks and even some fungus at the rim of a lens won't really.

And generally, don't be hypersensitive or even fussy with minor flaws of a lens. Be happy that you can get it cheaply and enjoy it!

I own a lens that used to have fungus which was cleaned but some marks where the fungus ate into the lens surface remained. This is one of my best lenses performancewise!!


PostPosted: Fri Apr 11, 2014 3:59 pm    Post subject: Reply with quote

The baffle is a good idea I think, yes every little can help. It would be interesting to see comparison photos with and without.


PostPosted: Fri Apr 11, 2014 7:10 pm    Post subject: Reply with quote

philslizzy wrote:
The baffle is a good idea I think, yes every little can help. It would be interesting to see comparison photos with and without.


Baffles, revisited...

My experience with using „legacy” lenses on digital cameras is very limited as compared to most contributors here, but what little chance I’ve had to play around with them (on 4/3 and APS-C sensors) was enough to show that baffles improve IQ very noticeably. Many adapters are badly flocked indeed and on some the design is so thoughtless that the nickel-plated mounting ring is visible from the inside as well. It doesn’t really matter if the finish is black. Unless the surface is matte, it will reflect light to a degree or other.

But the smoothest and most reflective surface inside a digital camera is the sensor. It’s surface is far more reflective than film and using manual focus lenses with a large image circle introduces much extraneous light into the "mirror" chamber. Much, if not most, of this light is useless for image-producing purposes because it hits the sensor at such a sharp angle that it isn’t even picked up. Instead, it is left to bounce back and forth at all possible angles against the reflective surfaces between the lens and the sensor. The result is great loss of contrast and flare similar to using a lens without a hood.

The purpose of a baffle is not to reduce light as such, but to reduce the lens’ image circle so that its diameter is equal to the diagonal of the sensor. The desirable diameter of the opening on a baffle differs from lens to lens, as the lens' optical construction and, hence, the angle at which light emerges from it, is more important than either focal length or the diamter of the rear optical element. There is a good write up about the whole issue, including with-baffle and without-baffle photos, at: http://www.street-photo.fr/fr/materiel/27/35 (French - use Google translate).

And here is an example of what results can be obtained on a m4/3 sensor with the much-maligned Hexanon 40/1.8 with a baffle (opening: 13mm): http://www.street-photo.fr/fr/tests-et-comparatifs/7/7


PostPosted: Fri Apr 11, 2014 7:16 pm    Post subject: Reply with quote

I am still not convinced by baffles. One reason why is that with some lenses, the image circle increases a great deal when you stop them down. For instance the image circle of the Sonnar 4/135 is about 60mm at f8 but at f16 it is about 90mm. There is no decrease in contrast or IQ apart from very slight diffraction on an APS-C sensor. So I don't see much benefit really, going by this example.


PostPosted: Fri Apr 11, 2014 7:57 pm    Post subject: Reply with quote

iangreenhalgh1 wrote:
I am still not convinced by baffles. One reason why is that with some lenses, the image circle increases a great deal when you stop them down. For instance the image circle of the Sonnar 4/135 is about 60mm at f8 but at f16 it is about 90mm. There is no decrease in contrast or IQ apart from very slight diffraction on an APS-C sensor. So I don't see much benefit really, going by this example.


Ian, I've never investigated the issue of why baffles seem to add much IQ with some lenses and make almost no difference with others, but I strongly suspect it has to do with the lenses' optical construction and, especially, their focal length. My suspicion rests on two facts: Firstly, that the point of using a baffle is not to reduce the image circle as an end in itself, but to get rid of light rays that enter the camera at an angle that precludes their capture by the sensor. As the sensor's light-sensitive elements are placed at the bottom of a "tube" of sorts, any light rays at a sharper angle than "x" (whatever the value of "x" may be) will just be reflected and scattered. Secondly, that the angle at which most light rays enter the camera is determined by the lens' FL - the greater it is, the more those rays are perpendicular to the film/sensor plane. With a wide-angle lens the light rays are far more scattered. Both Konica and Minolta used this optical feature in the light-metering systems. I suspect the impact of baffles may be inversely proportional to a given lens' focal length.

Now the FL of the lens you mention is such that placing a baffle on it would probably affect a very tiny proportion of the light rays coming out of it. I suspect the impact of using baffles would be more evident if you used a standard FL or even a moderate wide angle.

Anyhow... just thoughts.


PostPosted: Fri Apr 11, 2014 8:35 pm    Post subject: Reply with quote

Old lenses most certainly need hoods, teles definitely included.
So do new lenses for that matter.
There is a reason even 2-element achromats came with immense hoods.
In any kind of strong outdoor light, even if the lens is in shadow and with the light from behind, the reflected glare will reduce contrast, and, I am convinced, reduce apparent sharpness.
Maybe this does not apply as much in poor light, but even with an overcast sky I notice this.
And there is no better option than a decent metal hood to protect the front element. I have dropped lots of lenses over forty years. I have had a few bent hoods but no bent filter rings or shattered front elements.
Hoods are very cheap. There really is no reason not to have one.


PostPosted: Fri Apr 11, 2014 9:52 pm    Post subject: Reply with quote

Question
Would a baffle at the rear-filter end make any difference to how a mirror lens performed?


PostPosted: Sat Apr 12, 2014 3:06 am    Post subject: Reply with quote

Baffle is reported to correct exposure metering problem with some lenses


PostPosted: Sat Apr 12, 2014 5:47 am    Post subject: Reply with quote

Quote:
they also keep the raindrops off the front element

Isn't this is what your wife or husband is for... Laughing

I like this point
Quote:
And generally, don't be hypersensitive or even fussy with minor flaws of a lens. Be happy that you can get it cheaply and enjoy it!


I never use hoods and my images suffer for it on occasion. I find that I am starting to want to use a tripod more under certain circumstances....macro and with my mirror lenses.

I have never tried a "baffle" on any lens.


PostPosted: Sat Apr 12, 2014 8:13 am    Post subject: Reply with quote

Sometimes I take photos, some other times I talk on the internet Laughing


PostPosted: Sun Apr 13, 2014 2:11 am    Post subject: Reply with quote

tromboads wrote:
Sometimes I take photos, some other times I talk on the internet Laughing


Em, thanks for that bit of information.


Has anyone determined whether or not light intensity is reduced by a baffle? If so, and maybe even if not, the baffle may act similarly to a diaphragm to increase sharpness, contrast, and depth of field.


PostPosted: Sun Apr 13, 2014 12:35 pm    Post subject: Reply with quote

woodrim wrote:

Has anyone determined whether or not light intensity is reduced by a baffle? If so, and maybe even if not, the baffle may act similarly to a diaphragm to increase sharpness, contrast, and depth of field.


In response to your question, I would say that to understand how a baffle works, it is important to distinguish between two categories of light: One is the light contained within the theoretical image circle determined by the dimensions of the sensor in your camera; and the other is all the light from beyond this circle.

Ideally, the baffle should only eliminate light of the second category. Most of this light is not picked up by the sensor because A) the sensor’s pixel sensors are shielded and located below the sensor’s highly reflective surface, and B) most of it hits the sensor at a sharp angle and is deflected by the sensor's highly polished surface, leaving it to bounce back and forth between the sensor and the lens’ rear optical element (and whatever other reflective surface it lands on), causing clouding, loss of contrast and apparent sharpness.

Light of the first category, the one that is unaffected by the presence of the baffle, is the one that is actually captured by the sensor and is used to produce an image. As the baffle doesn't affect this light, it follows that the baffle doesn’t act like an aperture and is not going to influence image sharpness in the same manner as closing down an aperture would, nor will it affect DOF in any manner. Rather, it works similarly to a lens hood, but acts on light that has already passed through the lens.

So, the answer to your question about whether the baffle will reduce light intensity is “yes”. But will this affect your image? My experience says “no” Why? Because the baffle doesn’t affect light picked up by the sensor. The way to demonstrate this is to use baffles with progressively smaller openings and observe your camera’s light meter as you go along. The meter won’t pick up any light falloff until the baffle opening becomes small enough to encroach on the sensor's image circle. If you continue beyond this point you will end up with vignetting. So the right opening size is the one just before you reach this point. This size has to be determined individually for every lens, because it is not strictly related to the diameter of the rear optical element, but rather to the lens’ internal optical construction, which determines the angle at which the light emerges into the camera.

Of course, in practice there isn’t a point where one category of light is neatly separated from the other. The best one can hope to achieve is to eliminate as much of the extraneous light as possible, without affecting the light that the sensor picks up.

I hope this helps to clarify things. There is a good explanation of the entire issue at http://forum.fourthirdsphoto.com/keepers/57126-legacy-lens-baffle-size.html
Scroll down the page and see the photos of contributor dnas.


PostPosted: Wed May 07, 2014 12:52 pm    Post subject: Reply with quote

I think this Kipon adapter sponsoring multiple leaves aperture makes sense. You can use it as baffle or close more.
Price is somehow high, nevertheless it's IMHO worth it. I don't know which mounts are available but EOS:

Presentation: http://sonyalphanex.blogspot.com/2010/12/nex-canon-eos-lens-aperture-control.html
85 EUR (i have no connection with the seller): Click here to see on Ebay.de


PostPosted: Wed May 07, 2014 1:53 pm    Post subject: Reply with quote

I had seen that adapter, but didn't realize it might be intended as a baffle. Seems an interesting approach since the diaphragm can be closed until a difference in light is detected.


PostPosted: Wed May 07, 2014 6:25 pm    Post subject: Reply with quote

maybe OT: Is there (here?) good noob guide about using MF lenses in DSLR world? I got it all - few DSLR cameras, about 50 different MF lenses and little (or no) skill...


PostPosted: Wed May 07, 2014 6:58 pm    Post subject: Reply with quote

No published guide for our mad little corner.
I'm not sure that a very useful guide is publishable.
As for taking pictures, IMHO these are just ordinary photography problems that are mostly independent of equipment.
There are hundreds of good guides published in the last 100 years that can be helpful with the usual real problems - exposure, lighting, composition, etc. Its the same stuff whether you have an 8x10 view camera or AF lenses on digital.

This is a fine one -

http://www.goodreads.com/book/show/20501.The_Camera

My father-in-law was one of his students in the 1940's. He (FIL) took great pictures.


PostPosted: Wed May 07, 2014 8:40 pm    Post subject: Reply with quote

DrBB wrote:
maybe OT: Is there (here?) good noob guide about using MF lenses in DSLR world? I got it all - few DSLR cameras, about 50 different MF lenses and little (or no) skill...


I think the entire forum is a guide, but not organised in any way. You can search for topic and usually come up with several responses. Also, don't hesitate in asking questions, there's always someone ready to explain things.


PostPosted: Thu May 08, 2014 2:01 am    Post subject: Reply with quote

Using a teleobjective shade with a 50mm helps a lot to reduce the circle and the flare. This solution works only with cropped sensor of course.
I have a collection of Takumars with their hood . The filter thread is always 49 mm. A 55mm 1.8 was really improved by the hood of a 150mm f4 on a micro4/3 camera.


PostPosted: Sat May 09, 2015 8:06 am    Post subject: Reply with quote

Filters added to the list Smile.


PostPosted: Sat May 09, 2015 12:13 pm    Post subject: Reply with quote

Pancolart,

For the "greenhorns" of photography your guidelines are at least not bad I would say.
Sometimes I am also somehow amused about people who are lacking of basic knowledge of the subject and believe that a more expensive equipment produces automatically the better result and are discussing about the pro's and con's of this or that lens and/or camera.
Elderly people (coming from the analog world) have more likely a slighter better understanding of the basics. Especially your last hint about filters and their possible effects on the final picture is widely underestimated among the average younger digital photographer.

This topic reminds me somehow of the times when I stepped in the world of polarizing filters some decades ago.
Especially polarizing filters may increase the quality of a picture dramatically and there is nothing you can do afterwards, if the picture was taken without such "magic" tool. So, finally a picture using the worst lens ever produced may be far better when taken with a polarizing filter compared to a picture of the best and most expensive lens ever produced without the filter.

I also cannot see automatically any difference in quality, if the picture was taken with my first digital camera some 15 years ago compared to pictures of my newest most expensive camera if the full picture is only displayed on the monitor. However, if I want to produce huge paper prints the difference is more than obvious. Finally, I am still totally convinced that there is still no digital camera in place which is able to beat the best film/scanner combination. That's what I know for sure.

Just my 2 cents...