Is a center filter a must for 90mm lens on a 4x5 Field camera.
Is a center filter a must for 90mm lens on a 4x5 Field camera.
Depends on your needs and capabilities.Originally Posted by HughC
Many who work only in black-and-white don't bother with a center filter for 90mm and even shorter lenses on 4x5. Instead, any balancing of fall-off that is needed gets done during printing. Same with color negative film for many; fall-off gets corrected when printing or in post. Important here, of course, is to realize the the edges of the image circle will get less exposure than the center and to give adequate exposure when needed to ensure the shadow detail at the extremes of the image circle.
Where center filters are considered more necessary is when working with color transparency materials. With these, there is no possibility for dealing with the fall-off unless one scans and digitally post-processes. Still, with the more limited dynamic range and latitude of transparency film, that's often not a good solution either.
Not using a center filter also means you can use the filter size that fits your lens when filters are needed. Many center filters step-up the filter size to a larger one to prevent vignetting. This means you'll need a set of larger, more-expensive filters.
FWIW, I have never used a center filter on either 90mm or my 75mm lenses. I've perfected what I call a "center burn" that I use in the darkroom while printing. Basically, it's just "zooming" a card with a hole cut in the middle up and down over the optical center of an image that exhibits unwanted fall-off.
Best,
Doremus
This has been discussed a lot on this FORUM. You can use the SEARCH feature (upper right-hand corner of this screen) to view these.
Like many options/choices/decisions in photography, it's easy enough to test for yourself. You are the judge:
http://www.subclub.org/fujinon/center4.htm
In a nutshell, for color negatives or slides it is a must for me. For b&w it is not. Can you get away without it? Most times yes. Also if you scan the negatives you can also correct it in digital in most but the most extreme cases.
It's both an esthetic choice and a technical one. Depends on the look you want, the film type, and how you intend to reproduce the image. I personally used one for both black and white and color film with a 90mm lens. These are most typically a stop and a half of neutral density for that focal length. Even with color neg film you can potentially get falloff color crossover issues in the corners without CF correction. And that kind of issue can't be corrected by simple dodging and burning, or easily if at all digitally either. Just be aware of it. Whether it matters to you or not is a separate question.
Keep in mind that center filters add to the size required for other filters like a polarizer or contrast filters for BW.
Flickr Home Page: https://www.flickr.com/photos/alanklein2000/albums
Keep in mind that center filters can be added AFTER filters like a polarizer or contrast filters for BW.
There is no law against it where I live anyway
I shoot b&w and bought a CF for use with my 90mm lens.
However, I tried with and without and although there is a difference, I found it not to be worth it.
So, in answer to is it a MUST - then for b&w the answer is no - but it is a nice to have.
I do use the same CF with a 65 and 47 mm lenses and I put the CF after the coloured filter.
Martin
I had no problem at all using a same size standard contrast filter behind the wider center filter itself. No optical issues at all. It is hypothetically possible, doing so, that you might get a little mechanical vignetting with some extreme rise or similar movement movement using a very wipe aperture - never happened to me, or is likely too in ordinary applications. CF's don't even work properly at wide apertures; so putting them in front of another filter is a non-issue; they're designed for usage around f/16 to f/22 or so.
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