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View Full Version : stepup rings, how big to avoid coverage loss?



Daniel_Buck
5-Jun-2008, 00:13
Most of my lenses have a 52mm filter size, so I would like to step them all up a few sizes and use larger filters, in the hopes of getting a bit more coverage out of them (because sometimes I use 2 filters together, color plus polarizer). I've been using 52mm filters (that I just happen to have from a while back) and have been holding off on my filter purchases until I stabilize out my usual bunch of hiking lenses. I think I've done so, and I'm ready to purchase the filters. One of each: strong yellow, strong green, strong red, and a polarizer.


So my question is this, when stacking two filters on top of each other, roughly how large would I need to go (starting at 52mm) to avoid cutting back the existing coverage of the lens itself (with no filters). By that I mean, would 52-67 step-up with two 67m filters stacked to avoid decreasing my coverage? If not 67m, how about 77mm? Is there any way to calculate this? Or would it probably be the safest bet to go with 77mm and not even think about 67m?

And on the same line of thought (and a possible reason to go 77mm versus 67m), my one odd ball lens that has larger threads (90mm super angulon) has 67mm threads. I'd like to sometimes run a single filter on this lens, and again keep as much coverage as possible. Would a 67-77 step-up plus one filter yield a bit more coverage than just using a native 67mm sized filter?

I know it will probably be brought up, but I'd like to avoid square filters. I tried them awhile back with medium format, and I didn't enjoy using them to much. I've determined that I'm a screw-on-filter kind of guy :)

Thanks for any insight on this!

IanG
5-Jun-2008, 00:24
This is where systems like the Cokin P series come into their own, one filter holder with adaptors for each filter thread. I've been using mine for over 25 years now with no problems.

Ian

Greg Lockrey
5-Jun-2008, 00:48
I would think that the only lens you would have to concern yourself with coverage would be any wide angle like the super angulon. I would try a pair of 67's on that lens and see how far you can move that lens verses w/o filters. Those other lenses wouldn't be a concern by using 52-67 step up rings. If you in fact need to go to 77mm while using a pair on the 90, then a 67 polarizer would be your small lens with 77's for your color lenses and then use the step up ring for everything else. Personally I use a 67mm polarizer and that old Kodak square filter holder with a collapsable sunshade and I only notice a slight vignetting while using the 90mm. Collapsing the shade is usually enough to get arid of the vignetting. You could take the shade off if you have to, but I never had to. I believe the opening for the 3" square filter holder is around 75mm.

Emmanuel BIGLER
5-Jun-2008, 01:56
I'm using step-up rings on a regular basis.
If you use a wide-angle lens in the 100° and more, you'll find the required external ring diameter by looking at the manufacturer's specs for circular-graded centre-filters that compensate light fall-off.
For example I have such a filter for a 6.8-75 mm Rodenstock Grandagon-N ; filter thread is a modest 58mm but the front thread of the filter is a 77 mm size.
For the bigger 4.5-75mm model, front lens ring is 67mm and the filter size is 86 mm.

The complete range is liste here for Linos Rodenstock ; Schneider has the same products with similar specs:
http://www.linos.com/pages/no_cache/home/shop-optik/rodenstock-foto-objektive/analoge-fachfotografie/?sid=13379&cHash=571ffb8782#sid13379

58 up to 77 and 67 up to 86, this makes quite a steep step-up ;) but those filters are for use up to the extreme edge of the image circle.

If you use a standard lens covering 70-75 degrees, you'll probably be safe with a 58 to 67 step-up ring, for example.

Ash
5-Jun-2008, 02:02
Go for the huge Cokin filters that can lay flat on your lens, or else look for single-step filters, like 52-77mm or something like that. You will be paying more, but you won't get vignetting.

Doremus Scudder
5-Jun-2008, 02:21
Daniel,

Stacking filters on lenses of normal and longer focal lengths is not a problem at all. You do not need to step-up to a larger (and proportionally more expensive, heavier) filters to avoid coverage loss on these lenses.

Wide angle lenses can vignette when stacking filters. Theses lenses almost always have larger filter sizes than 52mm to start with anyway. (My Super-Angulon 90mm f8 takes 67mm filters, and vignettes slightly when two filters are stacked and any movements are used.)

I rarely have problems stacking filters (52mm) on my 135mm lenses (one Nikkor-W, one Ektar wide field... the Ektar is actually stepped-down from series VII to 52mm).

Lenses that are designed for 52mm filters are likely of a design and focal length that eliminates the need for stepping-up to avoid vignetting.

Maybe you should do some tests and see which lenses you have that really have vignetting problems when the filters are stacked before you decide what filters to buy in what size.

FWIW, I do a lot of backpacking and long hiking with my 4x5 and five or more lenses. My choice of lenses has been influenced by filter sizes. I have standardized on two sets of filters, 52mm and 67mm. I carry at least six of each, in folding cases: yellow, orange, green, red, polarizer and a blue or cyan filter. I searched everyone's favorite auction site for a while till I found B+W coated filters with brass rings. They are simply better and easier to use than aluminum-ring filters, plus the coating is a real advantage. I'm sure Heliopan and other brands offer similar high-quality filters.

Hope the above helps somewhat,

Best,

Doremus Scudder

Daniel_Buck
5-Jun-2008, 08:42
Thanks for all the info!

I don't know for sure on my other lenses, but I know that on my 240 g-claron I loose a decent amount of coverage on my 8x10 when I use two filters. I'll have to try some of the other lenses with two filters and see if they loose much coverage. If they do, then I 'll use stepup rings to match the filter size of my 90mm super angulon.