high stop lenses
can anybody advise me on high f stop
think f64 and above
I would like to fit one onto a 35mm movie camera
I will be shooting macro so an adaptor will not be too hard to make for pretty much any lens
I know that there are process lenses such as apo ronar with high stops
but I believe that the large intended format and long focal length
will not resolve well on the small 35mm film
are there any smaller format lenses designed to optimally shoot at really high stops
I don't understand why one could not use long focal lengths in 35mm cinematograpgy. Or do you refer to the fact that lenses designed for large formats yield lesser resolution than lenses designed for small fotmats?
The minimum absolute size of a standard aperture is technically given. That is the reason that you won't find smaller apertures than you got at those shorter focal lenght lenses.
An alternative approach to looking for lenses with extreme small apertures is mounting a additional small aperture just in front of the front lens.
The most sound approach though is to mount a smaller (drilled) aperture inside the lens at the original aperture location. With some lenses that location is easy to access. You just have to find an appropriate way to fix that accessory aperture at that location.
Robin, what are you trying to accomplish? In particular, what magnification do you want to work at?
Has anyone explained diffraction to you? At f/64 diffraction limits the best resolution possible in the center of the field to approximately 23 lp/mm. The best resolution possible off-axis is lower. At 1:1 and f/64 set, the effective aperture will be f/128 and the best resolution possible in the center of the field will be 12 lp/mm.
Why do you want to shoot at a tiny aperture? What problem do you think that will solve for you?
How are you going to light your subject? Electronic flash is possible if you're shooting single frame (animation). Otherwise you're stuck with continuous sources. I'm not familiar with the latest most best, so can't say anything.
In addition to what Dan pointed out above, when doing close-up photography, the diffraction is worse than expected from the indicated aperture on the lens per the relationship below.
EFFECTIVE APERTURE = MARKED APERTURE * (MAGNIFICATION + 1)
I always try and keep aperture as open as possible, and rarely go narrower than 5.6-8 on crop digital, 8-11 on 135, 11-16 on 120, and 22 on 4x5, for the diffraction problems. But if you're shooting movies, res is lower so maybe you can get away with it for higher DOF.
But as IC said, effective aperture gets narrower with magnification anyway. The only way to get decent DOF with macro is to a) stack digitally, b) tilt/swing, or c) get shorter focal length lenses. Regular retrofocus SLR wide-angles won't work with macro, that why there exist dedicated macro lenses like Canon's MP-E 65 for 1-5x mag, and the Olympus OM 38mm and 20mm lenses. They won't focus to infinity, but they'll get you up to 12x mag, there's a reason they'll still set you back $500+...
Of course they do. Some can be used on short extension tubes or on bellows facing normally or reversed. Others, e.g., the 24/2.8 Nikkor, can be used only reversed. For more details, see Nikon's instruction manual for the PB-4 bellows.
Originally Posted by Dr Croubie
Because they're retrofocus the working distance (lens-to-subject) can never be less than their native mount's register. The downside to using them is that because their pupillary magnification is far from unity the relationship between aperture set and effective aperture depends on the lens' orientation (facing normally, reversed) and isn't as is implicit in my post #3 in this thread and as stated explicitly by ic-racer above. For further discussion, see Lester Lefkowitz' book The Manual of Closeup Photography. For examples, see the PB-4 instruction manual.
Clarification: Can't work easily with macro, which I should have written. And by that I mainly meant with extension tubes. Turning from infinity to MFD on most of my widest lenses only moves the elements by 1-2mm away from the film plane at most. With my thinnest extension tube being something like 10mm thick or so, I've never been able to focus on anything with lenses wider than 28mm. (I've got my RokiBowYang 35/1.4 just working with 10mm tubes, and my Super Ozeck II Macro 28/2.8 works ok, but not the Mir 20/2.5 or Tokina 17/3.5, and I've just realised I don't have a 24mm prime. I'd best rectify that with GAS).
Not as nice as with the OM 20mm macro, which you can rack out to 12x and the working-distance doesn't change much with focussing, stays fairly constant at "bugger-all mm". Still I want one, for when I need to take photos of match-heads and all.
But yeah, I wasn't thinking about reversed, which I've also done a bit of (manual-lenses only, there are ways to use EF but it gets complicated). And with the whole thing of pupil factors and effective apertures and all that, I'm too lazy to work it all out so I don't even bother attempting macro without accurate TTL metering, and only use flash when I can chimp on the digital...
Anyway, the OP hasn't clarified exactly how close 'macro' will be, we're all presuming that the smaller aperture is to get bigger DOF, but there could be other reasons like to purposefully introduce diffraction (in which case, may I suggest a pinhole?)
wow; pinhole filming ;sounds interesting
Originally Posted by rbrigham
I've never seen a reference to E. Weston making his own apertures. Anything in his biographies/daybooks refer to commercial products.
Originally Posted by Mustafa Umut Sarac
The small stop and long exposures were results of the films available at the time.