To Center Filter or not to Center Filter...that is the question;)

[audioexcels]

I have read the countless, though of course, countable threads on the use or lack of a use of a center filter. Here is the data I have collected, but I do not know if it is all and I was hoping to make a nice thread to see what others feel about using center filters. Hence, the title of the thread, to center filter or not to center filter.

1) Center filters "need" a step up filter. Myth or fact?

2) Center filters, when shooting b/w are often times not used since the vignetting is easily dealt with.

3) Center filters depend on the lens being used. For example, two different 65mm (take any focal length of choice with same image circle) lenses with equal coverage may not have similar illuminating characteristics, hence, the need to use the CF for one but not the other.

4) Center filters can actually be a deficit to the final image. I read his when reading about the 110XL and how use of a CF did only harm to their images with 8X10. The writer/s have even gone so far as to say not to use one period.



These are the 4 primary things I can recall through all my readings. My question for the group is a simple one. It can involve answering these questions/statements. But one thing I would be most interested in is this:

1) What lenses "in particular" do you find a need for a CF? I am interested in 5X7 and larger formats, but this is not necessary for this thread as I am most interested in personal use whether it be 4X5 or the larger than smallest format of LF photography.


2) What lenses are "known" to need/require a CF in the Large Format world?


3) Is there a certain trend by manufacturer per need of CF OR is it a lens by lens situation. In other words, is a Rodenstock lens one that most always need a CF, but the Nikkors do not (all hypothetical with relation to brand a/b/c/d).


I believe this is all my mind can come to at this time. I'll leave it up to the group from here.

Thanks everyone for your contributions!!!

[Ron Marshall]

I have found, for negative film on 4x5, that falloff is not objectionable for 75mm and longer focal lenths. For my 55mm I always use a CF. For transparency, I used a CF for shorter than 110mm.

My 75mm lens design has light falloff correcponding to cosine to the third power, and I don't often use large movements. If either of these didn't apply I might use the CF more on the 75.

[cotdt]

the CF depends on the focal length of the lens and the size of the film. it's cuz the light from the lens will be hitting the corners of the film at an angle, the steeper the angle the more the light loss. the shorter the focal length of the lens, the steeper the angle. anything above 75mm you won't need a CF, but the ultrawides need it if you want to prevent vignetting. you get the same effect when you use movements on the view camera. simple trigonometry can predict how much vignetting would occur.

personally, i love a bit of vignetting. it makes the picture more romantic.

[Justin Black]

I almost always use a CF on my 58mm XL. When I use my 75mm, however, I consider whether even illumination best suits the composition, or if the natural falloff toward the edges will benefit it. It is ultimately a creative decision like any other. FYI, I shoot 4x5, and mostly color transparency.

[audioexcels]

I almost always use a CF on my 58mm XL. When I use my 75mm, however, I consider whether even illumination best suits the composition, or if the natural falloff toward the edges will benefit it. It is ultimately a creative decision like any other. FYI, I shoot 4x5, and mostly color transparency.

Your images are rediculous...simply delicious. What do you use to scan them onto the site and in general, how are they scanned? Very gorgeous stuff.

Thanks to you and others so far. I hope this thread spins along in an interesting way.

So from the three of you, with E6, I seem to gather:

110mm and lower needs a CF
75mm and higher no or not necessarily a need for a CF

[cotdt]

audioexcels, that 110mm lens was used on an 8x10. On a 4x5, there is no vignetting whatsoever. The larger 8x10 film required a more extreme light angle, so you get vignetting. For 4x5, anything lower than 75mm you should consider using a CF.

[audioexcels]

audioexcels, that 110mm lens was used on an 8x10. On a 4x5, there is no vignetting whatsoever. The larger 8x10 film required a more extreme light angle, so you get vignetting. For 4x5, anything lower than 75mm you should consider using a CF.

What would be the recommended size (minimum) for 5X7 and how about the 72XL since that is a more exclusive lens for both the 4X5 and 5X7 formats. In other words, take 75mm as a minimum on 4X5. Would the 90mm be the minimum w/out CF for 5X7, and then the 110/120 for 810, etc.?

[timparkin]

I'm using an 80SSXL with the centre filter as all of the feedback I've received has suggested it is important. It's probably more important on the Super Symmar range than the Super Angulon because light falls off faster with the Super Symmar (something to do with clever lens pupil design on the angulons means Cos^3 fall off where super symmar is Cos^4 - this is from memory so it's probably wrong in some way)

Also, some pictures will benefit from some 'burn in' of the edges wheras some other images that include solid areas of consistent brightness (i.e. a desert sky?) will make the fall off obvious where it isn't wanted..

[Ole Tjugen]

The shortest lens I use on 5x7" is a 90mm Super Angulon. On B&W there is no need for a center filter, but with E6 I would at least consider it. I have recently got hold of a relatively low-cost center filter which I will be trying out, but since I received it either the weather has been atrocious, I have been sick, or (as right now) I have been offshore at work.

Update on that will follow as soon as I get a chance to shoot and develop two E6 5x7" shots - one with, one without.

On a "tangential subject", if there were a center filter for the old 120mm f:6.8 Angulon I would seriously consider using that even if I've never seen a need for one with the 121mm f:8 Super Angulon on 5x7". It's all about the light falloff characteristics: Old, small, simple WA lenses have falloff close to cos^4, while the "wasp waist" Super Angulons and similar approach cos^3. That makes a lot of difference in the far corners.

The step-up filter is only indirectly related to this, and has to do with physical vignetting from a (relatively) thick narrow filter rim. A step-up ring builds less thickness than a filter, and allows the filter rim to be positioned further from the lens' edge. This reduces the risk of physical vignetting.

[David A. Goldfarb]

I usually use a center filter on 4x5" with 75mm or shorter lenses, and occasionally with 90mm if, say, I'm using a lot of front rise. Occasionally if I'm shooting B&W and can't afford the extra 1.5 stops, I'll shoot without the filter. On 6x17 I use a center filter with 90mm or shorter, and it usually makes a very significant difference.

I don't use a step-up ring with my center filters.

I don't have a center filter that works with the wide lenses I use for 8x10", but if I had one, I'd use it. I tend to shoot only B&W with my widest lenses in that format, so I compensate as needed in the darkroom, and the same goes for 11x14" and 7x17".