New to LF questions part Deux

[Bob Bell]

These are a second set of questions so bare with my second thread.

Lens Hoods: I use them on every lens that I own in the smaller formats, I notice in LF there isn't a lot of mention of them. I know hoods, in addition to providing some protection, often allow higher levels of contrast and control off axis flair. What are the common solutions here? Screw in B+W hoods for each lens size?

Filters: I have Heliopan K Circ Pol's. I know they are problematic in 35 and MF on very wide lenses due to curvature of the lens changing the angle to polarized light. Will I have that problem with a 90mm? I know how to fix it in photoshop, its just quite a bit of work. .

Vignetting: How tolerant are large format lenses to normal sized filter mounts in relation to vignetting? Such as a 77mm on a step up on a 67mm filter size lens. This also relates to the Lens Hood question.

What is the filter thread on the back of some lens for?

Thx again for your patience with my new LF user questions. Some of the threads I have found touch on things but its more conjecture than definitive statements.

[Gordon Moat]

I already owned several metal Nikon hoods with 52mm filter sizing. So on my 135mm f5.6, I added a step up ring to allow fitting the Nikon hoods (usually an HN-1 or HN-2). A compendium might be a better solution, or possibly that clip on Ebony item with the board. Unfortunately as I add longer lenses, the filter sizes, and hood sizes, get larger. I still like the compact sized round hoods, so I might standardize on 72mm sizes for my bigger lenses.

Other odd items I have are a Cokin P holder, with a few different adapter sizes depending upon threading. I also recently tried out one of their plastic fixed hoods. Another alternative is the Lee bellows in Cokin P size, which functions sort of like a compendium.

Ciao!

Gordon Moat
A G Studio (http://www.allgstudio.com)

[John Kasaian]

I use a hat, but with wide angle lenses that can be problematic. An exhibitionist with a raincoat works well. Just position him in front of the sun or reflective surfaces before fine focusing to make sure he's not in the shot :rolleyes: If you can't find an exhibitionist (a bail bondsman can usually supply a few references) you might be able to obtain a "rubenesque" mother-in-law as an alternative :eek:

[Ron Marshall]

Lens Hoods: Screw-in or clip-on or compendium (like a bellows)

Filters: The sky may vary in brighness when a polariser is used and this is the same in all formats, just depends on the lighting conditions.

Vignetting: It depends on the image circle of the particular lens. If the lens has lots of extra coverage a bit of filter vignetting ins't important.

What is the filter thread on the back of some lens for? On some lenses the front element may contact a filter, unless a special filter is used. That is the case with my SS XL 110.

[Brian Ellis]

A compendium shade is probably the best solution but they're kind of a pain to attach and use, at least the one I had for a Linhof Technika was a pain. I don't think those little round shades that screw onto the lens do a whole lot of good in large format (probably not in 35mm either). Lee makes a lens shade (actually several I think) that function much like a compendium. You buy an adapter for each filter size on your lenses (or buy only one for your largest size and use step down rings for the others). Then the shade screws into the adapter. I used that system too and it worked pretty well but I'm not up on all the wide angle and other versions, when I bought mine there was only one.

The threads on the back that you mention are for filters, some lenses will allow you to attach a filter on the rear rather than the front when the front glass protrudes too far to allow a front filter to be used.

I also used the Ebony clip-on item someone mentioned. It doesn't do anything that your hand can't do equally well in terms of shading. Its only advantage is that you can position it and then check the ground glass for vignetting, it's hard to do that with your hand since after checking with your hand in position you have to use your hands to put the film holder in the camera.

The advantage of a good shade is that it doesn't just stop direct light from striking the lens, you can do that with your hand. A good shade will prevent all extraneous light from striking the lens, including for example diffused light on a cloudy day that's coming from all directions.

[walter23]

Lens Hoods: I use them on every lens that I own in the smaller formats, I notice in LF there isn't a lot of mention of them. I know hoods, in addition to providing some protection, often allow higher levels of contrast and control off axis flair. What are the common solutions here? Screw in B+W hoods for each lens size?

I usually just shade the lens with a hand-held dark slide if I'm in a position where I'm worried about flare ;) You'll always have a dark slide readily available if you're shooting in regular film holders.


Filters: I have Heliopan K Circ Pol's. I know they are problematic in 35 and MF on very wide lenses due to curvature of the lens changing the angle to polarized light. Will I have that problem with a 90mm? I know how to fix it in photoshop, its just quite a bit of work. .

That's nothing to do with lens curvature or anything weird like that. It has to do with the amount of polarized light in the sky. Maximum polarized light is at 90 degrees from the sun (in either direction) and minimal is directly towards and 180 degrees away from (with the sun at your back). There's a gradual transition across the sky, and with a wide or ultrawide lens you're going to see this when you use a polarizer. It's an intrinsic property of the sky, not anything to do with optics.


Vignetting: How tolerant are large format lenses to normal sized filter mounts in relation to vignetting? Such as a 77mm on a step up on a 67mm filter size lens. This also relates to the Lens Hood question.

You might lose some movements to vignetting, and you might see it in extreme wide angle cases. I've used the cokin P system (big bulky rectangular filter holder) on my lenses (even the 90) and I haven't had any problems with normal landscape movements (a bit of shift/rise to adjust composition and some forward tilt).

[Gene McCluney]

Almost 100% of LF photography is done with the camera on a tripod, with a cable release. In this situation it is quite easy to use your hand or a dark slide to shield the camera lens from direct sunlight, as you can stand beside the camera, rather than in back looking thru a viewfinder. Lens shades can cause vignetting when you use movements such as front rise, or tilt, which is very common technique in LF photography. You can't always see this vignetting with the lens wide open for focusing, but it shows up when you stop way down for taking the photo. The practice of developing LF b/w films to a more vigorous contrast than minature (35mm) negatives somewhat compensates for possible overall "flare" due to extraneous light outside the image area.

[BrianShaw]

... you might be able to obtain a "rubenesque" mother-in-law as an alternative :eek:

I have one that I'm not currently using. I'll give it to the first person willing to pay the shipping cost. :D

p.s. This "lens hood" will even cook for you if you are nice to her!

[Bob Bell]

Thats too funny. Why do I think you won't honor a 7 day return policy :D

[David Karp]

I have made something like the Ebony sun shield by using a clip for holding documents that is supposed to attach to a computer monitor. It has a long flexible tube between two clips. One clip attaches to the front standard, the other to a gray card that I take with me in my backpack.

I also use 67mm rubber lens hoods with my 52mm lenses. The hoods have a 52-67mm step up ring on them. Just check for vignetting. If I remember right, John Sexton used rubber lens hoods on his lenses when we went out one afternoon during a workshop. I may be mistaken. That does not mean that they work or that you should do it because he does it. It does mean that it certainly does not hurt.

[Chris Strobel]

Bob I see you ordered the Shen-Hao 4x5.Thats what I use for 4x5.They do make a compendium hood for it, but I've found in my home studio a screw in rubber lens hood for my Nikkor 150mm works just fine.Now with my 8x10 C-1 the first shot I ever took with it in the same studio with a 300mm normal lens produced some pretty good flair on both sides of the neg, so much so that at first I thought I had light leaks.So I immediately hunted down the compendium hood that goes with the camera and bought it.Now all is well.Lee makes a filter/hood system that would work great on your Shen, but it aint cheap.I'd give the rubber hood a try first coupled with the dark slide or hat outdoors first.

Chris


These are a second set of questions so bare with my second thread.

Lens Hoods: I use them on every lens that I own in the smaller formats, I notice in LF there isn't a lot of mention of them. I know hoods, in addition to providing some protection, often allow higher levels of contrast and control off axis flair. What are the common solutions here? Screw in B+W hoods for each lens size?

Filters: I have Heliopan K Circ Pol's. I know they are problematic in 35 and MF on very wide lenses due to curvature of the lens changing the angle to polarized light. Will I have that problem with a 90mm? I know how to fix it in photoshop, its just quite a bit of work. .

Vignetting: How tolerant are large format lenses to normal sized filter mounts in relation to vignetting? Such as a 77mm on a step up on a 67mm filter size lens. This also relates to the Lens Hood question.

What is the filter thread on the back of some lens for?

Thx again for your patience with my new LF user questions. Some of the threads I have found touch on things but its more conjecture than definitive statements.

[Robert A. Zeichner]

I've done a lot of experimenting recently on the topic of lens shades and what I have concluded is this: While round shades, both fixed and collapsable are better than no shade at all, they fall short of doing the most effective job in demanding situations. Picture if you will, looking at a scene on your ground glass and imagine where the image circle (projected cone of light) falls, oustside of your gg image. Without any shade, that is the extra (non image-forming light that is entering your lens and being projected toward the inside of your camera. Some of that light might strike the inside of the bellows. Depending on what the inside of your bellows looks like, that could be a source of bellows flare. But, the real culprit is all the extra light that is bouncing around inside your lens. With the most modern, multi-coated optics and proper treatment of the inside of the lens barrel and the very edges of each glass element, it's not likely that this extra light will reduce the contrast of the image by a noticeable amount, but with older single and uncoated optics or newer lenses that have aged and developed low levels of haze on the elements due to evaporation of lubricants, condensation, etc., the contrast can be greatly reduced and I have proven it to myself with my experiments. This was the impetus behind my latest article in Photo Techniques on constructing a more effective lens shade. In it, I describe a shade made from a miniature barn door assembly from an old lighting fixture. The advantage with this is that you can adjust, by observation through the clipped corners of your gg, exactly where the leaves of the barn door need to be in order to exclude as much of the non image-forming light as is possible. That changes with every set up because the symmetry of that adjustment must follow the movements you have applied to that scene. It also changes with different formats (aspect ratios) of film. Consider this: Not counting the coverage beyond the minimum required for any panoramic format where the width of the film is twice the height, half the light entering the lens will never strike the film! That is the reason why this technique is now my standard method of shading for all my lenses on my view cameras.

[GPS]

Robert, despite of your article you will always encounter this amateur approach - the hat, the dark slide, etc. is enough... The majority of photographers don't have the direct experience with really efficient lens hoods. They just don't care to put a lot of effort to efficient lens shading. Those who make their own efficient lens hoods are just few, unfortunately.

[Louie Powell]

Hoods: I have a double clip - basically, two of those heavy-duty office clips with their handles connected together. I clip it onto the front standard of my camera, and then attach a sheet of dark gray foam to the other end. The clip can be articulated to position the foam to shade the lens. When not in use, the foam is used to cushion the ground glass on my camera. If the foam is too small, then I use a gray card instead.

Filters - I don't get excited about filters, but just in case, I have a set of Cokin P filters and a filter mount that fits all my lenses.

LF lenses vignette just like smaller format lenses. All of my lenses have the same front thread, so one Cokin adaptor fits everything.

It is possible to attach filters to the back of the lens, and that is advantageous when using gels, especially if you don't have a gel holder and use the fallback approach (a bit of tape).

[Bob Bell]

Robert, despite of your article you will always encounter this amateur approach - the hat, the dark slide, etc. is enough... The majority of photographers don't have the direct experience with really efficient lens hoods. They just don't care to put a lot of effort to efficient lens shading. Those who make their own efficient lens hoods are just few, unfortunately.

I am curious about this. What is a very effecienct hood in Large Format? I know the manufacturer's hoods on telephoto and super telephoto lenses are quite effecient and dedicated to each lens. I would like a solid metal or plastic hood that is the longest length it can be without vignetting at the largest aperture. If no one is making those commercially than what can be done?

[GPS]

Well Bob, even the manufacturer's hoods on telephotos in 35mm format are far from being optimal lens hoods. I make my own (was doing so the last 15 years) lens hoods. Contact me by PM if you want to know more. Will be happy to help you.

[Gordon Moat]

If you look at the video and motion imaging world, you can find matte boxes and French flags. Those solutions are similar to compendiums. They do work quite well, though I am less certain if they would be a good choice on a view camera. All of these are fairly expensive. Some are quite bulky or heavy.

Determining the best lens shade/hood is tough. Those round metal Nikon shades I use pack very small into a camera bag, and add very little weight to the overall kit. They are also fast and easy to install onto a lens. My feeling is that any lens shade is better than none. I would probably consider a compendium, or barndoors, or matte box solution as a better performing choice, though all those take up more room, weigh more, and cost more. Finding that price to performance and size to convenience balance will be different for every person.

Ciao!

Gordon Moat
A G Studio (http://www.allgstudio.com)

[Chris Strobel]

Ansel Adams, Bret Weston, Jay Dussard, Edward Weston, Ray McSaveny, and Howard Bond, who I've seen work in person or in documentaries, all were shading their lenses with a darkslide.I'd hardly call them amatuers IMHO


Robert, despite of your article you will always encounter this amateur approach - the hat, the dark slide, etc. is enough... The majority of photographers don't have the direct experience with really efficient lens hoods. They just don't care to put a lot of effort to efficient lens shading. Those who make their own efficient lens hoods are just few, unfortunately.

[Helen Bach]

Shading your lens from direct sun, if the sun isn't in the shot, is the simplest and most effective thing that you can do: the essential minimum. I think that it is worth knowing the effect of going further with lens shading so that you can make your own decision on whether or not you need to do it. Efficient lens shading with matte boxes, mattes and eyebrows is part of everyday practice for cinematographers, but to put it into perspective my Ebony RWE45 cost quite a lot less than the cheapest matte box system I have for ciné, with the exception of the matte box for my Bolex RXs.

Here are a couple of other, recent threads on lens shading: one (http://www.largeformatphotography.info/forum/showthread.php?t=24147) and the other. (http://www.largeformatphotography.info/forum/showthread.php?t=23254) The second one has a link to a longer thread on lens hood design.

Best,
Helen

[GPS]

Ansel Adams, Bret Weston, Jay Dussard, Edward Weston, Ray McSaveny, and Howard Bond, who I've seen work in person or in documentaries, all were shading their lenses with a darkslide.I'd hardly call them amatuers IMHO

While they are not amateurs their way of shading lens as you discribe it - and that's what I was commenting - is an amateur way.