ND filter on long lenses for lowering shutter speed

[alpshiker]

I am looking for a way to avoid using the difficult low speeds 1/8-1/4-1/2 with long lenses (these speeds produce unsharp images). I thought of using a +3 Ø ND grey filter. However, I am not sure a filter won't alter image quality when used on a 300-450 or 600mm lens. I have once had a 360 shot blurred on one side because I inserted a color correction filter aslant in the Cokin holder, so I am not using them any more. I think using the Cokin +3Ø ND that I have may not be the best idea, for the risk of reflexions on the filter too, but what about a good treated screw in filter? Should it preserve the long lens quality?

[armin_seeholzer]

Hi Paul

 

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I only can talk about 35mm long lenses, but if it works there it should

work also with LF.

But a warning aniway, it works only with the best filters like B/W,

Rodenstock, Heliopan, Nikon.

I had not good results with cokin and Hoya!

[doremus_scudder1]

Paul,

 

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You should have no problem using good-quality optical glass ND

filters on any lens. Scew-on filters are best to insure parallelism.

I am, however, a little confused as to what you are trying to

accomplish. In my experience, 1/8-1/4-1/2 second exposures are just

as sharp as any other speed as long as subject/camera movement and

film shift aren't degrading the image. Just what unsharpness are you

experiencing that is shutter-speed related? I'm curious. Maybe

there's something I missed here.

Regards, ;^D)

[alpshiker]

Thanks so far. Doremus I might have started another controversial discussion here, but I found that these low

speeds produce vibrations that are affecting image sharpness. Albeit not a problem on short lenses or large

stable cameras, this is a concern on extended 4x5 cameras where the lack of stiffness of the lensboard mount

is prone to be affected. Making exposures 1/30 and shorter or one second and longer helps solve the

problem.

[bill_glickman]

Paul, consider trying a Bogen 3252 / LONG LENS CAMERA SUPPORT

This will provide you with two points to stable the long rails. If

you are using newer lenses, I don't think the unsharpness is caused

by the shutter, but rather the tiny vibrations in the camera or

tripod. Have you tested this to see if longer exposures would solve

the problem? I shoot at these ss all the time and have not

experienced this. However, I have experienced unsharpness when not

shooting at the f stopd designed for that specific lenses. I always

uses dual support when I go past 360 on 4x5. Some of my 1200 Nikor

shots are super sharp on the VX.... But if you run this test and

find your hunch to be correct, I would be very intersted in knowing

this. I often suspected this, but never experienced it...

[doremus_scudder1]

Paul,

 

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Greetings from Vienna! I understand the possibility of vibrations

adversely affecting the image, but assumed this was a problem with

focal-plane shutters and reflex cameras with mirrors that flop around

during exposure. I would be interested in hearing in more detail

exactly what problems you seem to be having and if you have done any

tests to determine exactly which speeds are suspect, as well as

shutter size, bellows extension, type of camera and tripod mount,

etc. etc. I draw the bellows on my little field camera pretty long

sometimes and am now going to test and see if such shutter speeds do

cause image-degrading vibration. This may be yet another hidden

source of image degradation to deal with. Thanks in advance, ;^D)

[alpshiker]

Well, yes I have used a third arm, like the Bogen but self made and a bit

lighter (the Bogen clamps are a bit heavy outside the studio). It is not giving

me good results in light breeze, because all the tripod moves, but should be

enough to damper the shutter shake. But now that I have a second clamp and

extension on the VX, I would use a second tripod and that's excellent, even it's

harder to setup.

 

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I have made a simple test that a contributor to this forum suggested to me a while ago that

you can do also to check for shutter shake. Take a bit of electrical cord, cut

10-15 inches and strip the wire, then pull out one thread and fix it on the lens

or camera with some tape or by twisting it around something or pinching it with

the lens cap (careful with the glass!). Make it come forward by about 8

inches. Then operate your shutter and watch for any movement in the end of the wire.

I'd be surprised if it stays steady at all speeds, unless the camera is very

stiff. You can easily guess what the vibration, even small, can do to a long

lens shot. The vibration lasts only for a fraction of a second, so when you have

long exposure times, it does not affect image sharpness so much. I have seen

from a longtime that shots lasting a second and more are sharper than shots

taken at slow speeds. This was obvious when I used a Technika overly extended

with Wista Macro tube and only one tripod. Probably not a problem on heavier,

more rigid cameras.

[fw1]

I'm going to try that test with my Fuji 400T ; getting a loupe

noticeably improved the results with this lense, and maybe there is

something more to do with the camera stability. However I really do

not want to add any more items to my backpack - there's enough heavy

stuff in there already.

[dan_smith]

I am not sure from your post if you are looking at a .3 or a 3.0

neutral density filter. The .3 is a one stop filter while the 3.0 is

ten stops.

You might try wratten gel filters in a gel filter holder. They work

well and are easy to replace when the inevitable dropped filter lands

in the gravel.

 

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The quality if fine and photographers have been using them for

decaces with good results.

[alpshiker]

Dan, I thought of a -3 stops (or 8 x) grey filter, to make it worth it. Should make focussing pretty dark on a f12

lens ;-)

 

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David, I know what you mean. These packs are crazy!