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Frank_E
17-Jul-2011, 13:39
today at a camera swap meet I purchased a 90mm f8 Fujinon SW for the grand sum of $150 which I thought was a good deal. The shutter speeds seemed reasonable and the glass was clean. Didn't notice till I got home and examined it in better light that on the front element about half to 2/3 of the anti-reflective coating seems to have been rubbed off (worn off). So my question is how much of an impact might this have on my shots. I shoot 4x5 and only B&W.

I am aware that in the earlier days lenses were uncoated, however here I am dealing with a situation where the lens seems to be "half coated"

thanks for your feedback

Armin Seeholzer
17-Jul-2011, 13:44
Its no big deal at all, just use the lens an be happy!

Cheers Armin

Robert A. Zeichner
17-Jul-2011, 15:10
Optical coating reduces the amount of light reflected from the surface on which it is deposited. Uncoated glass reflects about 4% of the light striking it. Your lens is made up of a number of glass elements and as long as the rest of them are in good shape, transmission losses should be very minimal. You would do well to use a proper lens shade or better still, a compendium shade to eliminate non-image forming light from reaching the lens and ultimately, the film. People have been making wonderful photographs with totally uncoated lenses for over a hundred years, but still a proper shade will enhance contrast by reducing the unwanted light lying outside of the image area.

imagedowser
18-Jul-2011, 06:13
....... and you'll get better shadow detail. Def. use a shade.

Bob Salomon
18-Jul-2011, 07:20
Coatings are also a metal deposit on the lens that makes it harder to scratch. One of the original reasons for coating was to protect the surfaces.

cdholden
18-Jul-2011, 07:40
I thought coating was originally used for improved contrast in aerial recon sorties.
If used for protection, why do some have a softer coating than others? By design or by accident? My 203mm Ektar is one of the few I've seen that doesn't have coating damage. I've used a few with mottled coatings and some scratched from incorrect cleaning, but none seem to have a noticeable effect on film or paper.

8x10 user
18-Jul-2011, 18:20
I've always found that the coatings on lenses are softer then the glass and scratch easy. Of course there is that Schneider scratch resistant coating.

Tony Karnezis
18-Jul-2011, 20:50
You would do well to use a proper lens shade or better still, a compendium shade to eliminate non-image forming light from reaching the lens and ultimately, the film...a proper shade will enhance contrast by reducing the unwanted light lying outside of the image area.


....... and you'll get better shadow detail. Def. use a shade.

Frank, it sounds like you got a good deal on a nice lens. Here is a very nice article written by Robert demonstrating the effect of a good lens shade.

"Can better shades improve lens performance?
http://web.mac.com/razeichner/RAZP_large_pix/Shade_pg_1.html

GPS
19-Jul-2011, 00:29
I've always found that the coatings on lenses are softer then the glass and scratch easy. Of course there is that Schneider scratch resistant coating.

It's just an impression coming from the fact that scratches on a coating are easier to be seen than scratches on uncoated glass. As Bob says modern coatings are harder than the glass itself.

kirkmacatangay
19-Jul-2011, 07:59
Frank,

I was standing beside you when you got that lens. Still kicking myself for not getting it even though I did not have a budget for that type of lens. I do not think there will be an issue because the coating. Shoot with it and see if you like it.

Kirk

Ole Tjugen
19-Jul-2011, 14:14
Coatings are also a metal deposit on the lens that makes it harder to scratch. One of the original reasons for coating was to protect the surfaces.

The first (intentional) coatings were made with Magnesium fluoride, which is soft - so soft they were only used on internal surfaces.

The benefits of coating was discovered when some early special glasses tarnished when exposed to air, and it was found that this tarnish increased light transmission instead of reducing it, which was what one would expect. I have one of these lenses - a Schneider Xenar Typ D.

Frank_E
19-Jul-2011, 14:53
thank you for all of the feedback, this thread has been quite an education for me...

Kirk I sent you a PM...it's a small world...

Steve M Hostetter
19-Jul-2011, 21:05
Frank, it sounds like you got a good deal on a nice lens. Here is a very nice article written by Robert demonstrating the effect of a good lens shade.

"Can better shades improve lens performance?
http://web.mac.com/razeichner/RAZP_large_pix/Shade_pg_1.html

Should have used his hand too as an example for those of us that think a lens shade is a waste of time..

I mean ,, how does one use a lens hood on a 90mm lens or a 47mm or a 58mm or a 210mm 5.6 XL super symmar/ 210mm f8 super angulon which they don't even make one for..????

I do like the idea of the ebony flag on a stick

Tony Karnezis
19-Jul-2011, 23:39
I know what you mean. A priori, I wouldn't think a hood would help much with a wide angle lens.

Robert, what format did you use, and what was the widest lens you tested? Did you see a diminishing effect of the shade with wider lenses?

Uri A
20-Jul-2011, 00:32
This thread (http://www.largeformatphotography.info/forum/showthread.php?t=78528) may answer your question :)

Uri A
20-Jul-2011, 00:33
I used to assist a big-name fashion photog whose Pentax 67 lenses looked like someone had played soccer with them. No problem.

Tony Karnezis
20-Jul-2011, 00:42
This thread (http://www.largeformatphotography.info/forum/showthread.php?t=78528) may answer your question :)


I used to assist a big-name fashion photog whose Pentax 67 lenses looked like someone had played soccer with them. No problem.

Thanks Uri. That link is great. It reminds me of what Andrew Glover once told me: "Cleaning marks and scratches have more effect on the user than the film, in my experience."