lens/format for dummies

Dan Fromm said:

Jim, in my limited experience f/6.3 tessars have been better than f/4.5s.

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Probably so but when they were new the f4.5 were flagship items and the f6.3's were also-ran's for the folk who were poor. J

haris said:

Hello,

Yes I have read largeformatphotograhy.info site and some other resources, and still am confused in few things. And they are:

1. How to determine which focal lenght for what format? That is how to decide/calculate focal lenght of lens I need to have all movement of camera (including scheimpflug) and avoid vignetting?

2. How to determine/calculate ratio between bellows lenght/focal lenght of lens, that is to be able to focus lens from closest focus to infinity what bellows lenght I need?

3. How to determine wide lenses needed, and do I need long or telephoto lenses if I go to longer than normal lenses.

Basically, how to calculate what lens I need for particular camera format at same time keeping movement of camera, focusing through all focus range, and to have whole image and not cropped image or vignetting?

Next thing is reading lens charts. For example Schneider have lens info with telling "this lens is suitable for this format" and Rodenstock have lens charts which tells "this lens using with this format has tilt horizontal x vertical Y". How to read those charts, that is what shift in that situation means.

If answer will be too long, please, source of informations would be appreciated.

Thanks.

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A very simple way is to use the Pathagorum Theorum: Side a squared plus side b squared = side c squared.

This will give the diagonal measurement of a rectangle (the negative or sensor size).

Example using 4 X 5 - 16 (4 squared) plus 25 (5 squared) = 41. The square root of 41 is 6.402 (inches). 6.402 times 25.4 (metric conversion) is 162.61 sillymeters. A 150mm lens is considered "normal" for a 4 X 5 camera.

jimgalli said:

Probably so but when they were new the f4.5 were flagship items and the f6.3's were also-ran's for the folk who were poor. J

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True but irrelevant. I never took you for the sort of ignorant yuppie scum that, not knowing better, uses price as a measure of performance. You and I both know that this isn't always the case. Yuppie scum assume that po' folks like me, who have, use, and like, cheap f/6.3 Tessars don't know what's good. And in fact I use some of my old lenses pour epater les bourgeois.

Eric Beltrando, whose site you like, has calculated coverage and performance for a variety of tessar types. His curves show that f/6.3ers beat f/4.5ers. When I told him I'd got an f/6.3 Saphir, he remarked that it should be outstanding across the field wide open.

Good thing it was 5 after 12:00 when you said that. Nobody calls me ignorant yuppie scum before noon! Actually now that I think of it, any tessar is bougeois no matter the aperture. I have damn few Tessars in the lens vault.

Dan Fromm said:

True but irrelevant. I never took you for the sort of ignorant yuppie scum that, not knowing better, uses price as a measure of performance. You and I both know that this isn't always the case. Yuppie scum assume that po' folks like me, who have, use, and like, cheap f/6.3 Tessars don't know what's good. And in fact I use some of my old lenses pour epater les bourgeois.

Eric Beltrando, whose site you like, has calculated coverage and performance for a variety of tessar types. His curves show that f/6.3ers beat f/4.5ers. When I told him I'd got an f/6.3 Saphir, he remarked that it should be outstanding across the field wide open.

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Jim, for the record, I never said that you were ignorant yuppie scum. Having met you, I know very well that you're not ignorant, not yuppie, not scum.

There, feel better?

Time zzzones, gentlemen. It's hard to read intent on the Web.

HB - good info on avoiding very wide angle lenses with little 4x5 experience. I will keep that in mind, unless I find one I can't refuse. I won't give up on it prematurely.

Haris, if you ever run into the Kodak 3A postcard size cameras, they typically have a 170 mm lens. They can be very inexpensive. I have no idea what your market would be like, or if you'd find it easier to shop on eBay. Since they have been around so long, they may be easier to find. Don't pay alot, because one week they may command good prices, and the next week, the guy who won on eBay won't be overbidding as he doesn't need one that week.

Many variations, my general rule on trying to discern on the Web which lens one has is that the one that has a sloping metal disc around the lens and no glass visible (iris & shutter in front of the glass) has a meniscus (probably achromat) lens. I think they are f/11. Not sure

The next level up that I can recognize on the web has a Bausch & Lomb Rapid Rectilinear lens. Distinct glass visible, often in Kodak or EKCo Ball Bearing Shutter (good and bad; they seem to work as found, just not well, 2 speeds, sort of, plus B + T). If there is a good photo, there is a mechanical vignette disc limiting the clear diameter of the glass. Some say US 4 for aperture minimum which is f/8.

The next level of lens is an anastigmat, f/7.7 is a common one. Usually found in a multi-speed shutter. One of the better lenses supplied on this type of camera. The camera variation that carries this often has the additional descriptor 'Special' in the camera name.

There are even more variations and exceptions to the above, but the above helped me ID two by sight.

I ran into someone here and on largeformat...P.info who used a 3A anastigmat lens on a 4x5 Speed Graphic successfully & happily.

All three of these should cover 4x5 easily.

DannL here has made some nice 8x10 images with a 170 mm Rapid Rectilinear with one cell removed, making it roughly 350 mm, f/16 I think, and an achromat in that form of deconstruction.

I hesitate to suggest using lens reflections to recognize lens designs, because it takes experience and known samples on-hand to confirm what you think you see.

I got very confused with some known samples.

I also had an unfair sample...I expected a 6 element plasmat and was told later it was 8-element so I was very baffled.

HerrBremerhaven, Murray,

And all,

Thank you for all your help

Enjoy life