Effect of shutter type on image sharpness.

[IanG]

A serious question, I'm doing tests for a forth coming shoot. Initially I've been using a 17" (430mm) f5.6 ex military Telephoto (very late coated Dallmeyer) on a Speed Graphic as the lens has no shutter. My problem is I think the combination of a long focus lens and the vibration of the Graflex shutter rules out good results below 1/500 or maybe 1/200 if I'm very lucky, and initial tests lead me to think 1/100 would be better but there's not enough light.

I'd be happier with slower speeds and stopping right down but I'm shooting moving subjects so really what I'm asking is would a lens with a between the lens leaf shutter be a better option. That's my gut feeling so I have one on the way bu I'd like to hear others experiences.

Ian

[jp]

The shutter vibration on a speed graphic is basically as the shutter travel is done and is slowing down/stopping. I use a 19" lens on 8x10 with a speed graphic for a shutter no problem.

[Jim Jones]

Tests on a very small distant point light source at various speeds under conditions similar to your forthcoming shoot should settle the question. By moving the camera slightly between shots, it takes only one sheet of film.

[Jac@stafford.net]

A focal plane shutter has a much longer total exposure duration than a leaf shutter.
What Jim Jones said.

[IanG]

Thanks, I'll run some more tests later today and will also check how smoothly the shutter's running there may be room for some slight improvements. Part of the problem is I'm used to working with more sophisticated large focal plane shutters that run far smoother but my telephoto won't fit the cameras.

Ian

[LabRat]

A funny thing happened after I mounted a Dally 400mm f4.5 true tele on my 2X3 pre-anv SG... I did some test shots in bright sunlight, and noticed vertical blur on the negs, that varied speed to speed (and the blur followed the orientation of the camera)... Strangely, the higher speeds had more of this "effect", and at the slowest speed, the "effect" was less... The camera was on a sturdy (old metal Tiltall) tripod, cable release, and no wind... I had made some long exposure night shots that same evening, and they were sharp as a tack... I had also shot some images through a 161mm Tessar Ic, and looking at the neg at medium magnification, there was a hint of the blur, but much less...

The short of it was that a long lens on this Graflex FP revealed that there is some initial recoil when the shutter is fired, that seemed to increase with the higher tensions (like the camera was "hit" when the shutter released)...

I love this lens on this camera, so I went to work to reduce the problem... I made a oak mounting block that covered the bottom of the camera, and went along past the middle of the bed with different tripod screw mounting points, so I could change the balance point of the camera, and there was a larger seating area so more vibration could be transfered away to the tripod, switched to a more solid head that was more supported at the base, and used a MUCH bigger wooden tripod... But also added a ND filter to the lens so I could shoot SLOWER, not faster shutter speeds (where there was less recoil when the shutter was tripped)... All of this helped!!! (I wanted to add a leaf shutter to the 400mm, but the lens is too big for front mounting, and MUCH too big to fit on the tiny lensboard!!!)

I used to test shutter vibration on 35mm/telescope mounted astrocams by reflecting a stationary laser beam off the telescope's front element and watch how much the beam spot (on a distant wall) would deflect when the shutter was released, and find the "sweet spots" of balance. speeds, etc... (And I agree with the others that testing is in order... I would put a rollfilm back on your camera rig, and shoot frames at your common speeds, and see which one's are better/worse...)

But my 4X5 SG's and RB seem to be a little gentler when the shutter is released... (But the RB has that mirror...) If it's any comfort, the same day I was shooting, I had gone to an image show/sale, and was holding in my hands, an original print of Strand's "Bowls" that had the same vertical blur/multi highlight on an edge, as what I ended up with, so not only my problem!!!!! (I still would have bought the print if I had 2 grand to spare...)

Steve K

[Tobias Key]

My only experience of this is phenomenon is with Pentax 6x7's, but the principles should be the same. With these cameras 1/250th and faster would be my 'safe zone' for good results. 1/125th good on a tripod but 1/60th 1/30th 1/15th and 1/8th could be badly affected by vibration if you were not careful. It is useful to think in terms of what proportion of the exposure is affected by vibration, particularly when the shutter fully opens and closes again. 1/15th is always thought of as a the sour spot for 6x7's as the shutter opens fully, the exposure is quite long, and the whole camera is still shaking from the mirror slap! Slower speeds allow the vibration to subside and faster also make it less of an issue. The weight of the lens on your camera could also be an issue, making the front standard unstable, is there any way you could support the front standard more?

[IanG]

You raise an interesting point Steve, when I shot predominantly with my Mamiya 645's in the 1980's some shutter speeds were sharper hand held than on a tripod (unless you used the mirror lock). Working hand held dampens the vibrations unfortunately not a very practical option for this project.

I think you're right about the balance point, I know that's a huge issue if I try to use my 300mm f9 Nikon M on my Wista, it's why the press in the UK often used to use big Bertha cameras with telephoto lenses, the wooden bed as you describe. I'll look at other ways to dampen vibrations with the SG and make sure I've the brightest ground glass scree for optimum focusing.

JP's comments about using a SG shutter on a 10x8 camera effectively uses the central portion of the curtains travel.

Ian

[Jim Noel]

Your wooden block is approaching a solution. A good wooden tripod like an Otto which is not huge,but strong, should eliminate all vibrations. I have two different sizes,and a large Ries. The smallest Otto is as strong, and does a better job of dampening vibration than the large Ries. It is a matter of the type and shape of the wood used in the tripod.

[EdSawyer]

" I'm used to working with more sophisticated large focal plane shutters that run far smoother but my telephoto won't fit the cameras."

What type of cameras would these be? I am interested... (I have Graflex and Arca FP shutter LF cameras, so curious for others' experiences there.)

[IanG]

" I'm used to working with more sophisticated large focal plane shutters that run far smoother but my telephoto won't fit the cameras."

What type of cameras would these be? I am interested... (I have Graflex and Arca FP shutter LF cameras, so curious for others' experiences there.)

I've been working on Thornton Pickard SLR focal plane shutters, these are mostly modular so the entire shutter and mirror box comes out as a whole, like this:

http://lostlabours.co.uk/photography/cameras/images/ruby-14sm.jpg

This is a self capping shutter with two blinds and bares more resemblance to later Leica and then 35mm & MF SLR cloth focal plane shutters, so quite different to a Graflex FP shutter and they run very much smoother,

I think the earlier FP shutter on my ore-Anniversary Speed Graphic is smoother than the Pacemaker but my camera is a wide angle special and has less bellows extension than other Speed graphics.

http://lostlabours.co.uk/photography/cameras/images/speedgraphic.jpg

The earlier Graflex shutter has fewer slits, and a shorter curtain but uses different tensions so is slower to use in terms of adjusting the shutter speeds.

Ian

[IanG]

Your wooden block is approaching a solution. A good wooden tripod like an Otto which is not huge,but strong, should eliminate all vibrations. I have two different sizes,and a large Ries. The smallest Otto is as strong, and does a better job of dampening vibration than the large Ries. It is a matter of the type and shape of the wood used in the tripod.

I think you're right about a wooden tripod Jim, I have a Gandolfi tripod with one of my 10x8 Agfa Ansco cameras sat on it across the room and it would be a far better option, the top platform is quite large, 9"x6". So i could put some rubber between the front bed and the platform.

Checking the camera for vibration I found the sliders holding the lens board in place allowed some movement so I tightened them up. Initially I'd used a Ground glass screen and fresnel but I had a second frame with a plain screen and the original glass which I reground and is now much brighter. As it's a Graflok back I compared both screens, critical focus was identical but the plain screen was much easier to focus there was no benefit using the one with a fresnel.

I've done a new test so will process the negatives tomorrow. The plain screen was definitely much easier to focus out in the field.

Ian

[Jac@stafford.net]

Checking the camera for vibration [...]

Just wondering, and not recommending the iPhone app 'Vibration'. It might be worthwhile a look.

In my humble experience any tripod with a rising center post is out of the question. Astronomers can inform us very much for steady setups. In the city I find enough ground vibration to consider these (http://www.digoliardi.net/vibration-suppression-pads.jpg) The orange part is a gummy compliant material; the rest is hard plastic. Frankly, I cannot tell if they work all so well. Perhaps others can.

[Michael Clark]

Are the gummy compliant material placed under the legs of the tripod to reduce ground vibrations.

[LabRat]

One factor I have found setting up telescopes/astrocams is that do you want to isolate a vibration source by inserting dampeners (rubber, etc) that will create a barrier for the vibration (useful if there is a ground vibration), or in this case, a camera that is the source, where creating a conduit that the vibration will move away from the source and be harmlessly dissipated in the system or grounded???

I have been taught that mass is a good vibration sink (as it takes more energy to move something massive and smaller amounts of energy get "lost"), but I have also found that things like old, lossy thinner wooden tripod legs + couplings transfer enough vibration away, but don't allow it to return or resonate (if barely stiff enough not to wobble, shift, or move)...

The laser test I described before speaks very well... Even a mounted laser pointer aiming at a lens filter that reflects to a nearby wall speaks volumes...

Steve K

[Jim C.]

In the city I find enough ground vibration to consider these (http://www.digoliardi.net/vibration-suppression-pads.jpg) The orange part is a gummy compliant material; the rest is hard plastic. Frankly, I cannot tell if they work all so well. Perhaps others can.

The orange gummy part is probably Sorbothane - http://www.sorbothane.com/material-properties.aspx

My buddy and I used it years ago on turntables and CD players as a vibration damper.

[mdarnton]

One thing that might be a consideration: I have a Graflex Super D that I used to use for available light work at the drop shutter speed (1/5). I never had any sharpness problem at all, which confused me a bit, given the kick that thing has. Just now, reading this thread, I realized that I was using a 30CM Heliar on that camera, and the lens itself weights quite a bit. I wonder now if the weight of the lens was damping camera movement, but also if in combination with that whether there was an aspect that the time period of the shutter's kick represented a relatively small percentage of the total exposure. If that's the case, you might actually be better off with a slower speed than a fast one? It might be worth trying.

[IanG]

One thing that might be a consideration: I have a Graflex Super D that I used to use for available light work at the drop shutter speed (1/5). I never had any sharpness problem at all, which confused me a bit, given the kick that thing has. Just now, reading this thread, I realized that I was using a 30CM Heliar on that camera, and the lens itself weights quite a bit. I wonder now if the weight of the lens was damping camera movement, but also if in combination with that whether there was an aspect that the time period of the shutter's kick represented a relatively small percentage of the total exposure. If that's the case, you might actually be better off with a slower speed than a fast one? It might be worth trying.

With this particular Pacemaker Speed Graphic the shutter is definitely smoother at slower speeds however slow speeds aren't an option as I'm shooting moving objects and need the speed, 1/125th at a minimum 1/250th seems fine allowing me to use the lens at around f16.

Ian

[EdSawyer]

IanG thanks for the info. The Arca Reflex uses a 2-curtain shutter which sounds similar to the Thorton-packard ones you mention. I am in the middle of overhauling mine, it's a complex but also elegant design to the way the shutter is timed/adjusted. But, it's a bit finicky. However when running right it seems quite smooth, though I haven't compared to the Pacemaker Speed and RB SuperDs I have in terms of vibration/etc. My guess is the thornton-packard design is probably similar to the Arca design, with curtains that meet together with adjustable gap width and fixed curtain speed/tension. I'll post some pics of the Arca set up soon, there are a few pics out on the web that show the basics of it but they are not too detailed.

In doing some more research online, the Arca Reflex shutter is similiar (though more refined/simplified) to the Minex shutter described here:

http://www.earlyphotography.co.uk/site/shutterm.html#Videx

it can go from Bulb up through 1/500th.

-Ed