Before purchasing my LF equipment, I am trying to find out what is the best way to end up with 2'x3' enlarged color print. (Using Velvea transapancy ISO 50) I was told by Schneider that a 4x5 camera with super high optics, ie. Super Symar XL asperical lenses with their new HIGH END BACK will produce atleast equal but usually better 2'x3' enlarged prints compared to 8x10 using traditional film holders and top end 8x10 lenses. The reasoning is due to a combination of both of these technological improvements available in 4x5. I was told the new asperical lenses provide a drastic improvement in sharpness which would be desirable for a 6x enlargement. The new HIGH END FILM back supposedly keeps the film and ground glass in the exact plane by vacuming the film on to the ground glass, then having the ground glass move back a distance equal to the thickness of the film. He said differences in tolerance even between the same manufacturer of film holders were drastic, and these were new film holders tested from all the manufacturers. (This what created the need fo a better back) Assuming this is true about the film holders and the new aspherical lenses, then it would make sense to me that the same print in 2'x3' could possibly look better with the smaller format. He claims he has seen this exact test side by side, and 4x5 is clearly the better enlarged print. (I still strugle with the 8x10 being 4x larger to start with, that seems a lot to overcome) If this is true, it would sure save me a lot of money and back strain going with a good 4x5 setup vs. 8x10. Of course the new HIGH END BACK is not cheap, $2,500 plus their film holders at $50 each. But this a lot less than the additional cost of satrting with 8x10 due to higher cost of lenses, camera, film, processing, etc. Of course I asked him if the asperical lenses and HIGH END BACK would be made for 8x10, he said there is no plans, not enough volume in 8x10 to justify the tooling cost. Does anyone else out there agree or disagree with this logic, or better yet has anyone tried these HIGH END BACKS w or w/o aspherical lenses?

-- Bill Glickman (Bglick@pclv.com), September 17, 1998

Answers

Bill,

I think the Schneider sales rep thinks you are a fish and he is trying to put a hook in your mouth. Next time you talk with him, ask him what use that product (the High End Back) was designed for. I know it wasn't developed for shooting landscapes. I use Fuji Velvia in the QuickLoad and regularly have my images blown up at least that large, and sometimes much, much larger. At 6x you will see no difference.

Ellis

-- Ellis (evphoto@insync.net), September 17, 1998.

With the large amount of *depth of focus* inherent in large format, I seriously doubt that a vaccuum film back would make much of a difference. So, all other things being equal, I would choose 8x10. But, of course, not all things are equal. 8x10 is a much more difficult format to handle than 4x5. So, unless your 8x10 technique is up to the task, stick with 4x5. Also, there are a great many labs that can do a good job of enlarging a 4x5 chrome to 2'x3', but that number dwindles to a precious few when it comes to dealing with 8x10. Actually, I'd say your choice of lab is much more important than your choice of format. Take it from someone who used to work in some of the best (most prestigious and expensive, anyway) labs in New York City. I would be interested to know what you are photographing and why you want 2'x3' prints.

-- Peter Hughes (leonine@redshift.com), September 17, 1998.

What apertures do you usually shoot at? Since most lenses are diffraction limited at the small apertures often used for large-format photography, it seems the advantages for the setup you describe would only exist under a very specific and not very commonly encountered set of circumstances.

-- Mike Dixon (burmashave@copmpuserve.com), September 17, 1998.

8x10 is two times larger than 4x5, not 4 times. When you enlarge something 2 times, you enlarge both dimensions, which results is 4 times the area. Its still a ratio of 2:1. If I remember correctly, the ANSI spec for film holder depth is .197 inches, and film is supposed to be .007 inches thick.

-- Ron Shaw (shaw9@llnl.gov), September 18, 1998.

Ron,

4"x5"=20 square inches; 8"x10"=80 square inches. QED an 8x10 negative has 4x times the emulsion area of a 4x5 negative.

-- Ellis (evphoto@insync.net), September 18, 1998.

Its still a ratio of 2:1. When you enlarge, you enlarge both directions., which of course results in 4 times the area, but linear dimensions, including grain, are 2:1 in size. Resolution is 2:1.

-- Ron Shaw (shaw9@llnl.gov), September 18, 1998.

I have found the folks who represent Schnieder to be accurate in what they have steered me towards as well as away from. Due to specific advice from some of them I have lenses from Nikon, Rodenstock as well as Schnieder. They seem to make a point of trying to match the clients needs to the product, moreso than most I have dealt with. All reports I have seen on the newest Schnieder glass, specifically the 110XL, show it to be excellent-better than anything out there. If their new back actually does what they say you might be better off using it as recommended. But there are a lot of variables to consider before making the decision. How precise is your focus? Does your back actually focus on the film plane as you shoot? Does your camera have some slop that will keep you from ultimate quality? Are you allowing other factors(flare, etc) to keep you from the highest quality available? If you aren't precise in your working habits the best gear won't really make much difference other than to let you know the theoretical limit should be within your grasp while the work product will disappoint you most of the time. If you can afford it, go for whatever you think will work the best, and with Schnieder & Rodenstock continually pushing the envelope on lens development you won't go wrong with their products.

-- Dan Smith (shooter@brigham.net), September 22, 1998.

Does anyone else agree with Ron's logic here? Film is basically a TWO dimensional medium (ignoring the emulsion depth) so you have to look at the area of the film (length x width) instead of a one dimensional linear measurement. Unless the object being imaged is rendered as only the size of a grain of film than you have to consider the area of film being used to record that image as more important than a simple linear measurement.

-- Ellis (evphoto@insync.net), September 22, 1998.

Actually, its not my logic. I try to avoid it logic most of the time. Whether its 2 or 4 times is academic anyway, as the two are locked together. When talking of enlargements, dont people quote linear dimensions? (2' x 3'). If you enlarge a 4x5 to 24x30, wouldnt it be 6 times? If you enlarge an 8x10 to 24x30, wouldnt it be 3 times? That seems sort of like 2:1 to me. To get back to Bills question, I still think 8x10 will give him a sharper and more grain free image at 2' x 3'. As far as grain size goes, it makes no difference how hi-tech the 4x5 back is. The grain is going to be the same size on both transparencies, so if 4x5 is used, its grain size in the final print will be 4 times the area of the grain in the final print from the 8x10. As far as sharpness goes, the 4x5 would have to have two times as much resolution to just equal the 8x10. It would have to have well over a hundred lp/mm to just equal the 8x10. I doubt it can, and certainly not if it is diffraction limited. Whether the 4x5 can make a decent print isnt the question. It will never be as good as 8x10 at the same final print size.

-- Ron Shaw (shaw9@llnl.gov), September 23, 1998.

I too am interested in the High End camera back, it seems like an interesting solution. I'm just unclear how much of a problem exist for which it is addressed. How does it drastically improve sharpness? My impression is that a camera lens, especially at small aperture, has a depth of field on both sides, ie. that their is a certain latitude, or depth of area at the film plane where focus would be sharp. In other words, if the film was moved a very small distance forward or back, the image would still be in focus. So why would a device that vacuums the film so that it will be held in position to very small tolerances make any difference in the sharpness of the image, if your film is in the depth of field of the lens? How many photographers, after a day of shooting 4x5s look at an enlarged print and feel disappointed that the sharpness could have been improved if only the film had been held more precisely? Have we all been suffering with poor film plane alignment and just not known how good it could be?

-- Larry Watson (larry@ora.com), September 25, 1998.

Im a bit skeptical about it myself. Almost any shot taken in LF is diffraction limited, unless you can shoot at F8 or F11. Not many shots will lend themselves to that large of an aperture.

-- Ron Shaw (shaw9@llnl.gov), September 25, 1998.

There is one situation where the Hi End Back would be clearly and undeniably superior and that is when you have the camera pointed straight down as in copy stand or macro situations. In this situation gravity often causes the film to sag downward out of the plane of focus. That's why professional copy cameras have vacuum backs. As for other situations I will just have to see. I purchased one of these backs but have only had it a couple of days. The materials and machining are very impressive. It's been a long time since I've seen anything with such impressive build quality.

-- Eric Shaver (eshaver@earthlink.net), May 17, 1999.