How to make sharp photographs with long lenses?greenspun.com : LUSENET : Large format photography : One Thread
This question was raised from a discussion started under the thread "Portable 300 mm lenses". As with Julio, we entered the subject of camera stability as an important aspect in the completion of a sharp photograph, I think it would be instructive to continue this discussion in the forum and hear what other photographers have to say and what hints they would provide. Julio pointed to me in a private mail that motion during pose can be caused by numerous factors, wind (very important), improper release cable operation, we could add improper tripod setting (on unstable vegetation or soil, snow, or in the flow of running water), undersized tripod. It is true that central shutters produce very little vibration. But on my opinion, they produce some. If this effect is negligible on short lenses, it is multiplicated on long focals, due to lever effect of the bellows extension and aggravated by the narrow angle of view of the lens. With long lenses when possible, I extend the pose to one second or longer to minimize this "motion" on the overall exposure time. Julio says he would think a heavy lens should dampen the vibration and I think this is partly right. If you have driven a car on a "corrugated iron" dirt road, you have noticed that at certain speeds your car moves smoothly while there is hell at the wheels level. But if you slow down, the car begins to shake with every little bump. I use sometimes on a Pentax 6x7 a heavy 400 mm. The weight absorbs the (strong) shutter shakes quite well at high speeds, but even with the sturdiest tripod and mirror up lock, there are slow speeds I must avoid. On a field view camera with extended bellows, I think the smaller and lighter the lens, the more stable the shot at slow speeds. But this is just my opinion and nothing scientific. I use a thin soft cloth release cable about 25 cm in a loop. I don't know if it transmits moves or not to the lens so I try not to move my hand during the pose. A 50 cm length would perhaps be safer but it gets easily caught in the vegetation. I have seen photographers use two tripods for long lens takings with studio type view cameras. I am personally not yet a user of lenses longer than 360 mm in LF and I would be interested in reading what you have experimented and what precaution you take when using 300, 450, 600 or longer lenses in the field. Is the shutter shake on (modern)LF lenses a reality or just an other myth? One of the specific question I would also ask in relation with long lenses is how do you manage with hyperfocal when you need the max DOF (exemple close trees and mountains in the back). Do you rely on what you see on the GG or do you use a DOF scale? Where do you place the point? By the way, happy New Year to all !
-- Paul Schilliger (firstname.lastname@example.org), December 29, 1999
The wind moving ther camera is more of a problem than "shutter shake". With very long non telephoto lenses It is best to use either two tripods (heavy and clumsy or a Kirk or Bogen/Manrotto telephoto support. this is essentially a small monopod with a ball joint at each end that attachs to one of your tripod legs via a Bogen/Manfrotto Avenger Superclamp and then to your camera. This works well. Andreas Feininger used a two legged device but the idea was still the same: support the camera at two points. Shielding the camera from the wind is also a good idea.
-- Ellis Vener (email@example.com), December 29, 1999.
I use the Nikkor 500mm, and 720mm lenses and three out of four photographs I shoot are very sharp. Here is what I do:
1. I use the cheapest lightest tripod Bogen makes because I pack all my gear into remote areas. I have attached a hook to the bottom of my center post to hang a rock bag from. I usually place between five and ten pounds of rock in it. Hooking a rock bag to the tripod legs is not good enough.
2. I have developed a method to insure my loupe really does focus on the camera side of the GG. I mark the setting on my loupe with red paint. I recalibrate each winter.
3. I have gone to great lengths to make sure that my GG focus plane is perfectly aligned with the film plane. I never do any lens tilts with these lens because some part of the picture will always go soft on me if I do.
4. I bought some 1/8 inch bungy cord at a mountain shop and tied both ends together with a backpack pull to from a large loop. I attach one end of the bungy loop to the front standard. I then run the cord underneath the tripod neck between the legs and attach the other end to the back standard. I draw the cord tight using the backpack pull to form a triangular bow in tension. Between the rock bag and the buggy cord I have a solid platform.
5. I always use the smallest stop the lens has which is f/64. The lenses are optimized at infinity so that is where I focus. I limit them to big grand senics (sp) at infinity.
6. I try to use around a 10 second exposure which eliminates any movement that the shutter may cause.
7. I use a very flexible 40 inch cable release and pray for calm. Very slowly I take up any slack in the release just before I plan to shoot. I then release the cable as slowly and smoothly as I can.
8. After I load the camera with film and cock the shutter I wait at between 30-60 sec for any vibrations to stop before I shoot.
Hope this helps.
-- Stephen Willard (firstname.lastname@example.org), December 31, 1999.
To Stephen Willard thanks for sharing your excellent, painstaking and common-sensical methods in dealing with vibration and movement re. long lenses. In an experiment that I did with one of the heaviest Gitzo tripods, (509 with long geared column) it was somewhat surprising that even though the very heavy long column was set at a flat low position on the tripod, restraining vibration of the column by placing a heavy object against it at the bottom also prevented - but not eliminated vibration. Additionally I found that the camera- head linkages or fixtures acted as 'elastic links', and that the camera bodies themselves were or appeared to be 'elastic' components. I think that this latter problem is often overlooked. As I use all formats, one of the links tested was a Hasselblad quick attachment fixture with custom plates fitted to the camera, -all formats. An Arca-Swiss QF proved slightly less prone to vibration.
The issue of shutter-shake on modern lenses probaby depends, among other things, on the asymmetry / geometry of the forces exerted upon any of the shutter components in the process of opening/closing. If the shutter were built so that all forces cancelled out, as for example by pulling the blades open by pulling at diametrically opposite ends with equal force, there should be no vibration. This is a question that the shutter / lens manufacturer should be best qualified to answer.
The above discussions and the universality of the concern (all formats) all point to the need for more sophisticated methods for measuring the rigidity /dampening characteristics of a photographic system. Today, performance specifications exist for lenses, at least from some if not all manufacturers, but with respect to vibration, rigidity and dampening characteristics, there are absolutely zero performance specs for cameras, tripods and other support components. This and that tripod are claimed to dampen vibrations, great, to what extent?, and is this true also at low temperatures which increase the rigidity of the polymeric matrix that embed the carbon fibers? Most unlikely. I hope you agree that it is time for manufacturers of cameras and of support components (tripods, heads, QF fixtures, etc.) to test their products and give the photographic community meaningful performance measurements -instead of marketing verbiage. Julio Fernandez
-- Julio Fernandez (email@example.com), January 02, 2000.