Filters and image quality

[brandon walker]

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I'd be interested in people's experience with filter use and image quality.

I have noticed that a front 77mm uv ( B+W MRC) seems to lower the IQ just a bit on my 280 f4 APO, have heard others say that a filter on the 180 3.4 APO does the same ( mines a series 7.5 so doesn't see filters) and that the version I 50 sum micron is formulated to be used with a (series VI) filter. Any opinions? (accepting there are other reasons to use filters than just protection etc)

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[lct]

As far as the Apo-Telyt-R 280/4 is concerned, a protective screw-in filter for the front lens element and a series 5.5 filter inserted in the filter drawer are integral parts of the lens design. For special lighting situations (e.g. point light sources in the image or in bright backlight), Leica recommend working without the protective front filter. The same advice may apply to any other lens IMHO.

Edited October 14, 2012 by lct

[wildlightphoto]

As far as the Apo-Telyt-R 280/4 is concerned, a protective screw-in filter for the front lens element and a series 5.5 filter inserted in the filter drawer are integral parts of the lens design.

 

Are you thinking of the 280mm f/2.8 APO? The front protective plate of my 280/4 is not user-removeable.

[brandon walker]

Thanks for your replies.

Doug, Im referring to the 280 f4 apo telyt: Id been using a 77mm filter infront of the built in protective element (maybe a bit over the top but in an effort to give greater protection I guess).

[lct]

(…) The front protective plate of my 280/4 is not user-removeable.

So is mine. I meant a built-in protective filter sorry.

[lct]

For special lighting situations (e.g. point light sources in the image or in bright backlight), Leica recommend working without the protective front filter (…)

Correction. In such situations, Leica recommend working without « an additional screw-in filter » (user's manual, page 19). Sorry again

[k-hawinkler]

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On the 280 f4 APO the builtin protective flat plate is bad enough.

 

http://www.l-camera-forum.com/leica-forum/2325979-post104.html

Edited April 2, 2013 by k-hawinkler

[brandon walker]

Thanks that is helpful. It certainly adds to the suggestion of avoiding additional flat filters in bright light sources, but as the post suggests removing or substituting the existing built in front protector (for a meniscus one) is not an option. Interestingly asahi pentax used to make "ghostless" UV filters built this way: I have a 49mm one. I must try it out against a flat UV filter on a digital SLR in bright light to see if it makes a difference.

[gyoung]

Thanks that is helpful. It certainly adds to the suggestion of avoiding additional flat filters in bright light sources, but as the post suggests removing or substituting the existing built in front protector (for a meniscus one) is not an option. Interestingly asahi pentax used to make "ghostless" UV filters built this way: I have a 49mm one. I must try it out against a flat UV filter on a digital SLR in bright light to see if it makes a difference.

 

I had a ghostless Pentax filter back in the 60s when I had a Pentax outfit, I am pretty sure I won it in a competition in the users magazine. I remember thinking it seemd to make no difference to other lenses with flat filters so didn't bother buying any more.

My own attitude to filters has always been to use a UV at least as protection, the lens might perform better without it, but a lens with a scratch on the front surface will likely perform worse

 

Gerry

[algrove]

OP, thanks for bringing this subject up.

 

I never realized their was a protective glass permanently place in front of the front element. I have just been dumbly using a B+W MRC UV on the front of it.

 

I had Leica recently send me a new lens manual and never opened it until your post.

 

Now that I have read the manual, has anyone had luck using the circular polarizer 5.5 series #13338?

[brandon walker]

Hi, yes I have used the series circ polariser on the lens which works brilliantly. It's very easy to rotate with a finger or thumb whilst holding the lens.

[sfage]

I do not use UV filters any more. I found the BW degraded sharpness noticeably on my Angenieux.

[wildlightphoto]

...My own attitude to filters has always been to use a UV at least as protection, the lens might perform better without it, but a lens with a scratch on the front surface will likely perform worse

 

I quit using UV filters for protection about 30 years ago and have not scratched any lenses.

 

A few years ago I was given a 560mm f/6.8 Telyt with a scratched front element (as I understand it the rock that scratched the lens would have gone right through any UV filter); this was one of the sharpest 560mm Telyts I've ever used. Likewise the 300mm f/4.5 ED I got from my brother, scratched by the TSA: no visible degradation.

 

OTOH I did see degraded image quality in every photo where I had used a UV filter.

 

What's really great about scratched lenses is that people are afraid the image quality produced by these lenses will be cr@p so they give them away or sell them for a song.

Edited April 3, 2013 by wildlightphoto

[gyoung]

OK, about time I did some tests myself, to try and convince myself!

Not that I don't believe you, but its hard to break the habits of about 50 years

 

Gerry

[algrove]

Likewise the 300mm f/4.5 ED I got from my brother, scratched by the TSA: no visible degradation.

 

So from this I see what I should do. Since the TSA hires some less than ideal people who must touch lens elements to give you an OK, we leave the UV on for TSA and then remove them for use only to remember to put them back on for the TSA. What a world we now live in.

[wildlightphoto]

So from this I see what I should do. Since the TSA hires some less than ideal people who must touch lens elements to give you an OK, we leave the UV on for TSA and then remove them for use only to remember to put them back on for the TSA. What a world we now live in.

 

Given that the camera the lens was mounted on was broken in half by the TSA I doubt a UV filter would have made any difference. My brother learned why I don't put cameras in checked bags.

[algrove]

Given that the camera the lens was mounted on was broken in half by the TSA I doubt a UV filter would have made any difference. My brother learned why I don't put cameras in checked bags.

 

OK, it never dawned on me someone would check good camera gear. I must say on rare occasion I was asked about what I photograph and about the gear, but in many travels it's only been two times with questions like that. One guy asked me how much all the gear cost in 2 different bags and I told him since it was old gear not much. He mainly was interested in the SWC Hassy and the 503CW and did not really notice the P45+.

[gisling]

Filter always creates small amount of focus shift, no filter is best

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[masjah]

Filter always creates small amount of focus shift, no filter is best

 

... unless of course, as is the case with the slot in filter of the 280/4, it is explicitly included in the computation of the design. Leica point out that removing this would adversely affect performance.

[gisling]

The focus shift caused by a filter is about one third of its thickness.

 

For example if the thickness of a filter is 0.6mm, then the focus shift is about 0.2mm. Hence the thinner the filter the better.