Minimum focus distance and shooting down.

[carlosmh1910]

Hello everyone,
I am a complete newbie to LF, but I've been shooting digital and some MF for a while. I like to take pictures of the ground and blow them up, but the LF cameras are so big, can I point them straight down at the ground? And if I can, what is the minimum focus distance?
I'm usually about 3 1/2 feet from the ground, at about 45mm (APC 1.6 crop). I bought a Sinar A1 that has 19" bellows I think. As I said, I don't know anything about LF except that it will allow me to enlarge the way I would like to. What focal length would the APC sized sensor equate to in LF?
Also, with the bellows, I've read something about image circle and focusing, so I don't know if it is even possible to tripod-mount the camera pointing down and focus so close to the ground. Anyway, sorry for the long and noobish questions. Hope someone can help.

Note: I bought the camera, but have no lens yet. Any ideas on focal length or quality of brands (since my work depends on sharp, little details) that I should buy for what I'm trying to do?

[Ole Tjugen]

Yes, you can point a LF camera straight down. The minimal focus distance is 4 times the focal length of the lens, measured from ground glass to subject. There are a few exceptions - some telephoto lenses can manage a bit closer since the nodal point is actually somewhere in front of the lens.

You're about 1m from the ground as I think (metric), so a lens a little shorter than 250mm would be fine. The focal length corresponding to your 45mm on APC format is a bit more difficult - with LF, you are in the macro range at those distances and the usual rule-of-thumb doesn't work.

Here's one shot on 9x12cm film (a little smaller than 4x5") with a 150mm lens, from about 1m up:

[carlosmh1910]

Thanks for the advice. You said that it would be macro, is that possible for a LF? Here is an example of what I'm trying to do.

[Leigh]

Basic optics...
The lens is closest to the film when focused at infinity. It moves away from the film as you focus on closer subjects.

The distance from the lensboard to the film when focused at infinity is roughly equal to the lens focal length, but is actually equal to the "flange focal length" (FFL) of the lens, which varies with the lens design. The FFL distance is given on the lens datasheets.

To focus on a subject close enough to the camera to yield a 1:1 image, i.e. the image on film is the same size as the actual subject, the lens must be advanced a distance equal to its focal length from the position when focused at infinity.

For example, if you have a 150mm lens, it will be roughly 150mm from the film when focused at infinity, and exactly 150mm farther from the film when focused for a 1:1 closeup.

To relate this to your camera, your minimum bellows draw must be short enough to accommodate the FFL of the lens if you want to focus on distant subjects, and must be long enough to accommodate the extension required for closeups.

For the type of work you're doing you might consider a "macro" lens. These designs are optimized for close-up work, as opposed to standard lenses that are optimized for more distant subjects, and will likely produce better detail for close-ups.

As to focal length, it will depend on the size of the subject you're shooting. A "normal" lens, corresponding roughly to a 50mm lens on a 35mm camera, is around 135mm to 150mm on a 4x5.

Yes, it is possible to point an LF camera straight down, but it may be inconvenient. You still must be able to see the ground glass. This might be easier with a 90° viewer which is available for some cameras, or you could make a simple one with just a mirror.

Orient the tripod so one leg is going straight back from the lens, and the other two are splayed out to the sides. A word of caution... Be sure to put a weight on the rear leg to prevent the assembly from tipping over; it may be front-heavy. Try to get the two front legs forward of the camera if possible.

I'm sure others will have many more suggestions.

Good luck with it.

- Leigh

[Jon Shiu]

One useful thing with view cameras is that you can use the front "rise" movement (ie a shift movement) so that you don't need to position the camera and tripod directly over the subject.

Jon

[carlosmh1910]

I've heard people talk about enlarger lenses, do these help? When you say 1:1, does that mean what is being exposed on the film matches the exact proportions of what is being shot? I think the sample photos I gave you are about a foot of ACTUAL ground distance. Again, thanks so much for the info!!!

[Ole Tjugen]

1:1 means the picture on the film is exactly the same size as teh object you photographed - so for 4x5" film, that means you have a picture os a 4" x 5" bit of the ground.

Distance from the subject depends on a lot of variables, which is why it makes more sense to speak about the relative size on film vs nature.

For instance, my picture shows about 50x150cm of ground - roughly 20" x 60". That makes the scale around 1:6 - 1cm on the film corresponds to 6cm on the ground. The fly in the lower right quadrant seems to confirm that - it's visible when you know where it is, and on the original it can be seen in glorious (?) detail...

[Joanna Carter]

1:1 is the ratio of the size of the object you are photographing to its size on the ground glass screen.

Unlike "ordinary" cameras, you can extend the bellows on a view camera to give you macro focusing, in much the same way that you could use extension tubes on an ordinary camera.

It is certainly possible, depending on the maximum bellows length available, to focus on the ground with something like a 210mm lens; much longer could be difficult to obtain enough bellows length with some cameras.

[carlosmh1910]

Thanks everyone for their input. You have made the scary leap into LF much less daunting. So, to make sure I am understanding this correctly, I have an example question. If I'm using a 180mm lens, and my film size is 4x5 (10.2x12.7cm), and the area on the ground which is in the frame is approximately 30x24cm (as an example).
That would be between a 1:2 and 1:3 ratio. So, I would need 180mm bellow draw to focus to infinity, and about 90mm more bellow draw to focus at 1:1.5? Thanks for your patience, I am just very new at this.

[Dan Fromm]

I've heard people talk about enlarger lenses, do these help? When you say 1:1, does that mean what is being exposed on the film matches the exact proportions of what is being shot? I think the sample photos I gave you are about a foot of ACTUAL ground distance. Again, thanks so much for the info!!!

Many of us use enlarger lenses for closeup photography. Some are pretty good and they can be much less expensive than LF macro lenses from the major manufacturers.

Several considerations: check the range of enlargements the lens you want to use is made for. For example, Schneider Componon and Componon-S enlarging lenses are made for enlargements of 8x - 12x. This corresponds to 1:8 to 1:12 when taking. Schneider Comparons are made for 2x - 6x, i.e., for taking at 1:2 - 1:6. So, for what you have in mind to do a Comparon may be preferable to a Componon or Componon-S. I don't meant to slight other makers' enlarging lenses, just don't have their relevant data ready to hand.

Taking the exposure. You'll probably want an enlarging lens in shutter or mounted in front of a shutter. Many of Schneider's enlarging lenses have cells that go directly into some size or other of Compur/Copal standard shutter. I think -- you'd better check -- that this is true of many of Rodenstock's enlarging lenses. No idea whether this is the case for, e.g., Fuji. The one El-Nikkor I have, a 105/5.6, can be front-mounted but its cells won't fit a standard shutter.

You might want to take a look at http://www.galerie-photo.com/1-lens-6x9-dan-fromm.html IIRC, I think I discuss front mounting and adapters there too.