lens shade, round, square, or rectangle?

[doc]

i'm to the point where i think i need a lens shade, and i would hope that i can get away with just one adjustable one, but maybe that is too much to ask. my len ses run from series VI to VIII and one about the size of a small coffee cup.

i notice that a lot of med and large format shades are square. i wonder if that is provide the optimal shading. i've seen some that look like bellows, but the o ne i was looking at was square, and 8*10 and 4*5 of course is rectangle. maybe i ought to find a retangle then? i could make one that is bellows type, but what rules do i follow to get optimal shading without problems? i think the dagor i'v e got is 70 degrees.

i'm often shooting in sage brush in deep canyons and on hills, many of the shots which appeal to me have a degree of back-light or low slanting light. it always seems to be in the lens. if i could get a big enough, long enough, lens shade o f the right shape, i think i could bring home the image. Also, it occurs to me t hat a good lens shade may aid contrast even in moderate bright situations, and i notice that modern lenses seem to have a kind of shade looking thing on the rea r element which raises the question: would an internal lens shade help. I also w onder if those corrigations in shades like bellows somehow help to break up eniv atable reflection off the front element even in low light situations. any sugges tions?

thanks, david

[Bob Salomon]

If you are asking for a view camera then you don't want a lens hood.

You want a compendium. This is a bellows or bag adjustable for length, shift, rise, fall, tilt and swing that attaches to the camera body and can follow the movements of the standards to avoid vignetting.

Linhof's also accept masks to cut the light striking the lens to exactly the area of the film to further reduce flare.

The other way some compendiums do this is to have a bellows extension equal to the cameras' and an opening the same size and shape as the film.

Using a lens hood on a camera whose front and back move is asking for very little flare protection and a great chance of vignetting.

[Ray Dunn]

Look into the Lee Filters slotted lens hood. The hood attaches to the lens with an adaptor ring, therefore eliminating any problems with following the movements of the front standard. The model I use has two slots for 2mm filters. The hood is self-supporting, and seems very sturdy even in high wind. Highly recommended. See their page at www.leefilters.com.

[N Dhananjay]

As explained above, don't use lens hoods which are optimized for a particular lens on a particular format (generally 35mm or medium) to cut down extraneous light as much as possible and leave just the image area intact. LF lenses have much larger image circles than the format they cover which means in general, there is always extra non- image forming light bouncing off thee camera bellows and heading in the direction of your film as flare. You need something adjustable like a compendium because you choose which part of the image circle to use - therefore you need to be able to crop out the rest. If you use wide angles frequently, Lee has a wide angle compendium which may be worth your time - the regular ones may encroach into the picture area even when they are fully retracted at which point they are unadjustable. It also has filter slots at the back. Be prepared to squint through the corners of the ground glass frame before each shot to make sure the bellows shade isn't infringing on the image area. If you're on a budget, the barn door type of gel filter holders is worth looking at (although bellows shade will block out more extraneous light - whether that improvement is worth almost a 10 fold difference in price is a question for you to answer). I'm not sure I understand what you mean by an internal shade but I don't know if something like that is going to work. Once the extraneous light has entered the lens and is projected out the back, its headed film-wards. Good, light absorbent bellows might absorb the non image forming light but some of it is going to end up on film as flare, degrading contrast. An internal shade is going to provide exactly the same purpose served by the bellows of your camera and I don't see how it will do it better. Non image forming light (primarily due to the larger image circle of LF lenses) will bounce off the 'internal shade' rather than off the camera bellows - but it still has nowhere to escape and will end up on film. You're much better off cutting the light out from ever reaching the lens to begin with. Hope this ramble helps. DJ

[Larry Huppert]

I second the recommendation for the Lee shades. Also, if you use multiple cameras, they are a universal solution. The wide angle shade is interesting, but Lee didn't really optimize the shade for wide angle in my opinion. I'm not sure it effectively works with anything much wider than 75mm ish, especially if you use movements. The aspect ratio of the shade is closer to 35mm format, so it's not an optimal match for 4x5. Lee has not given you a good way to use a center filter, and still use their shade (a difficult problem to solve). Also, in the version which has filter slot(s), the slots do not rotate independent from the shade. Since ND-grads are one of the most useful filters, this is a problem especially for architectural work. Bending cine-foil, or using pieces of mat board still works better for real wide angle needs.

[Tito Sobrinho.]

Hello: Edward Weston, Brett Weston and Ansel Adams in their large format techniques never had to use a lens hood or a compendium. Instead, they use their hats or the dark slide to shade their lenses. Best, Tito

[Erik Ryberg]

Hi David,

What I did is buy an old compendium bellows on ebay which was originally for an 8x10 linhof. The thing is enormous and expensive, but luckily for me this one needed a lot of work on the bellows so it was dirt cheap. I rigged up a simple mechanism to attach it to the front of my camera and cut out some mat board which I clip on the front as a mask, depending which lens I'm using.

The only trouble with this setup is that I tend to think I'm not vignetting when I am - it takes some practice. I'm actually not convinced that it does anything to the final prints that holding a dark slide over the lens wouldn't do, but the theory seems pretty good so I go with it anyway. Also, it is a lot easier to vignette with a dark slide since you can't easily look through the ground glass while you're holding it.

[Larry Huppert]

re: "they use their hats or the dark slide to shade their lenses"

I can see this technique working well with moderate to long focal length lenses. Did these masters use this technique with wide angle lenses? At 75mm and shorter, I imagine it would be very difficult to eyeball the placement of your hat so as not to vignette. When using wide angle lenses, even with something as static as a compendium, you have to be careful to hit that precise setting where it shades the lens, but isn't in the frame. With wide angle, I've also run into cases where the direction of the offending light source is coming from the corner of the frame such that directly blocking the light with a card, dark slide or hat always resulted in vignetting because I had to hold the card at a diagonal. In those cases, the right angled surfaces of a compendium could shade the lens much more effectively.

How about a hat made out of self supporting bellows material (like the Lee shades)? It would not only be adjustable to different head sizes, but could serve well as lens shade. I remember someone showing "fashion" bellows with designs as wild as leopard skin, so the hat wouldn't have to be plain black.

[Robert A. Zeichner]

There is a lot of sense in using a card or other flat object to shade the lens, in that you can observe exactly where you need to cast the shadow by simply looking at the lens. With wide lenses you may need to exercise caution, but you can still do it and for a lot less money and weight than hoods, shades or compendiums. When shooting into the light, this may require something fixed to the front of the lens, although you'll have to be real careful to observe the gg with the lens at taking aperture to make certain you're not vignetting. In the motion picture industry, camera operators use a french flag to do this. This is a flat black piece of aluminum on the end of a thin gooseneck that attaches to the top of the camera. As far as hats go, I prefer to keep that on my head to hide my thin spot.

[Brian Ellis]

Before you get the Lee hood, try to make sure that there is sufficient clearance between the bottom of the hood and your camera bed to permit the hood to be screwed onto your lenses. With my Tachihara the Lee hood worked with fine. With my Linhof Technika V it is very incovenient because with lenses the front of which don't extend beyond the front of the camera bed (in my case only my 210 mm lens extends beyond the front of the bed) there isn't enough clearance between the lenses and the bed to allow the hood to be screwed onto the lenses. To get the hood to work with this camera I have to go through various contortions such as using front rise and/or dropping the bed and tilting the lens. Bummer, because the Lee hood works well on the right camera, costs a lot less than most cmpendium shades, and with Lee filters provides a compact, light way of carrying a lot of filters in a small space. I highly recomend the Lee hood and filters, if (big if) your camera will accept them conveniently. Brian