The best way to capture the front and rear coatings on a len

[mo]

I have a few pancolar 2/50 lenses,from the various batches produced (I still have quite a few too collect) and I want to capture the true color of the glass and or its coating.Do any of you have a fool proof way of doing this?or have any pointers/techniques of how I can get a true representation of the coating on each lens?

When I look at each lens, some I could say are blue and some yellow but then there are some that look mixed. Basically I don't trust my own eyes .
Thanks for any help.

[visualopsins]

Set white balance using white card -- include white card in frame...

Multiple lenses one photo is easier for me to compare differences than separate photos of each lens.

[kds315*]

[mo]

[visualopsins]

Well was thinking about a photo of a piece of photo paper with the lenses arranged on top, each positioned best to display coating "color". In post processing, use white balance tool, click on photo paper.

[mo]

Ah ha, thanks for clearing that up,I am not at all familiar with photo paper and not really sure where I will find some (I guess somewhere on ebay) Sorry I am a bit dense but I appreciate the help as I want to do this as best I can.

[visualopsins]

And here I was thinking there'd be a piece of photo paper nearby.

That's what I use -- clever, eh? -- to set white balance same as paper that will be used for printing...

Well, maybe not so clever...

The idea is to get something reasonably white in the frame so it can be clicked with white balance tool in pp. Copy paper works. A white card. This will give accurate color to the coatings in the resulting photo. But that isn't really necessary for comparing coating colors of multiple lenses in a single photo... To get even more accurate color, try the Gretag-MacBeth color system -- it sets white balance for a number of colors, accounting for sensor sensitivity variation for different colors -- that's what Orio was using...

You're not dense! There's only some noise on the line...

[kds315*]

[mo]

Thanks for the advice from both of you,it really is appreciated.It won't happen that quickly but it will happen eventually.

[visualopsins]

My biggest problem photographing lenses is with reflections -- lens photos made outdoors among the fir trees makes the lenses appear fungus filled.

[mo]

Some reflections on the glass make for a more interesting image.

[visualopsins]

There is the experimental approach. Nobody knows what you may learn using that method!

[visualopsins]

[visualopsins]

The reflections of point-source light from each element can be different color. This is also seen in images exhibiting colorful lens flare.

[mo]

i think I have read about this,I have tried to count the reflections I see.Is there a failsafe way to count these light source reflections? Or is it a case of trial and error,too see which angle you shine it into the lens works the best.

[calvin83]

You can start with those lenses with known design. For example, a Tessar 50/2.8 with will show four reflections in front of the aperture if you view the lens from the front and three reflections in front of the aperture(one of them is a weak reflection from the cemented surface) if you view the lens from the back. For a Primoplan 58/1.9, you will see three reflections(one of them is a weak reflection from the cemented surface) in front of the aperture and four reflections in the back of aperture. You can find a list of lens diagrams here(there may be errors in the diagrams but most of them are correct) http://forum.mflenses.com/list-of-lens-diagrams-triplets-planars-and-hybrid-lenses-t22934.html .

Try to look at the reflections from difference angle. In my experience, my table lamp is better than a point light source. Use a magnifier or take a photo when it is hard to tell from naked eyes.

[mo]

Thanks Calvin,I have both those lenses so will compare too see if what I am looking at is the right reflection