Center filter question - usage on different formats

[Steve Goldstein]

Suppose I have a center-filter designed for a certain focal length LF lens. Will I get similar results using that center-filter on a shorter lens and a smaller format if the angle of view for the two focal lengths on the two formats is roughly equal? This question goes the other was as well, moving to a longer FL on a larger format.

Here's a specific example to help clarify my question. A 90mm lens on 4x5 and a 50mm lens on 6x7 (rollfilm) have quite comparable fields of view. So would a center filter meant for the 90mm on 4x5 properly correct a 50mm on 6x7? I'm aware the lens must be well stopped-down.

What prompted this crazy idea? The 50mm Mamiya 7 lens has 67mm filter threads, as does the 90mm f/8 Super-Angulon. Mamiya never offered center filters but Schneider did, and it occurred to me the Schneider IIIa or IIIb (depending which version of Schneider's documentation one consults) could match the Mamiya's 50mm lens. There's also a similar angle-of-view relationship between the M7's 43mm and the 75mm f/5.6 Super-Angulon, both of which also have 67mm threads, so the Schneider CF-III might be a match there.

For an example going the other way, consider the 72mm SAXL (4x5) and 150mm Nikkor-SW (8x10). The have similar fields of view on their respective formats and both have 95mm filter threads. Maybe Schneider's IVb, meant for the 72, will correct on the Nikkor (assuming one could find both the center filter and the Nikkor).

[r.e.]

I have a Mamiya 7II, but not the 50mm lens. Could I ask why you want to use a centre filter with it?

[Steve Goldstein]

I was just thinking that if the fields of view are the same then the fallof may be the same, so would be mostly correctable with a CF. It’s not really a big deal for me with black-and-white, and I rarely use the 50mm anyway, but struck me as an interesting question.

[xkaes]

What prompted this crazy idea?

That's not a crazy idea or question at all. It's the angle of view of the lens -- along with the structure of the lens and the film format -- that make the difference. I'll give you an example.

I have a 47mm for 4x5" film AND a 12mm for 35mm. They have the same angle of view -- 120°. I use the same 77mm center filter because they have the same fall-off.

BUT, the film formats are comparable AND both of them are NON-retro-focus lenses. My other 35mm lenses are retro-focus designs and are not really helped as much by CND filters.

But much has a lot to do with personal opinion. Some people only use CNDs on 4x5" lenses wider than 90mm -- but they would if the same lens was used on a larger film format. I use a weak CND filter on my 105mm on 4x5" -- stronger on my 75mm, etc.

The choice is up to you.

Check out: http://www.subclub.org/fujinon/center.htm

[Drew Wiley]

It's more complicated than that. But without attempting a technical answer, one can always experiment to find out the truth, provided the two given lenses are actually similar in front diameter filter thread. For example, the same 82mm 1.5 stop ND CF I used for a 120 Super-Angulon worked superbly for my Fujinon 90 SW, and even for a 55mm Pentax 67 lens using an 82 to 77 mm adapter. But different designs of even the same focal length wide angle LF lens from the same mfg might call for completely different CF's due to significantly different amounts of falloff. It's also affected by how far you stop down the lens when the filter is in place.

[r.e.]

It would be interesting to know what Bob Salomon thinks about this question. I don't want to purport to speak for him, but he may say that centre filters are designed with specific lenses in mind and are not necessarily interchangeable between brands, or indeed within a brand, even for the same focal length.

As a result of reading Bob's posts on the subject, my own practice has been to use the specified centre filter for a particular lens, although on his advice I regard Rodenstock and Heliopan centre filters as interchangeable. However, I've also read posts by people who say that they have had no problems using, for example, a Schneider centre filter on a Rodenstock lens. I have not had to purchase a centre filter for a lens, such as a Nikkor, for which no centre filter has been specified because Nikon didn't make centre filters, and apparently didn't recommend a brand and model for its lenses.

[xkaes]

...centre filters are designed with specific lenses in mind and are not necessarily interchangeable between brands, or indeed within a brand, even for the same focal length.

That certainly would be news to Hoya, Marumi, Heliopan, and others that made lots of CND filters -- in various strengths and diameters -- without any specific lens(es) in mind.

[r.e.]

That certainly would be news to Hoya, Marumi, Heliopan, and others that made lots of CND filters -- in various strengths and diameters -- without any specific lens(es) in mind.

Bob Salomon's posts on centre filters address Rodenstock, Schneider and Heliopan centre filters for large format lenses. You can read the posts yourself. There are quite a few of them. Note also the second last sentence of post #5 above. As I said, some people say that they have not had a problem with interchangeability in specific cases. The very existence of these posts should tell you that this is regarded an issue, whether you regard it as one or not.

My own centre filters are the ones recommended by the lens manufacturer so I haven't had to try interchangeability personally, but I have a Rodenstock lens where different generations of Rodenstock centre filters made it necessary to look into the issue. Indeed, I had a message exchange with Bob on the centre filter for the lens in question.

[Alan Klein]

Center filters page https://www.largeformatphotography.info/filters.html


Dan Fromm's center filter selection/discussion page: https://galerie-photo.com/center_fil...mat_lenses.pdf

[r.e.]

Dan Fromm's center filter selection/discussion page: https://galerie-photo.com/center_fil...mat_lenses.pdf

That document is a useful compilation of publicly available information. Beyond that, I have reservations about it. If you look at Fromm's posts, his actual hands-on experience with these centre filters is quite limited. His position on the issue that this thread raises is stated in this sentence: "Schneider and Rodenstock center filters aren’t particularly lens-specific, their makers’ propaganda notwithstanding." He doesn't explain what the basis is for alleging "propaganda" nor what "particularly" means. It's just a single sentence, bald-faced assertion. At one point, I raised this sentence with him in a thread, but I didn't receive a response.