PDA

View Full Version : Can bellows "stretch" lens?



Ken Grooms
24-Oct-2006, 18:45
I'm looking for a 75mm (35mm equivalent) lens for a 4x5 view camera. Does that mean I have to get a 250mm lens or can I get by with a 210mm + bellows? Thanks.
Ken

Andrew O'Neill
24-Oct-2006, 18:48
I don't understand your question...

Frank Petronio
24-Oct-2006, 18:56
Based on your questions, you really should read a basic book about large format photography. I'd like to think that there are no dumb questions in this classroom but if you're asking clueless questions like this, people are not going to respond very nicely after the fifth or sixth one...

Oh, and get Rodenstock lenses. They are the best. Don't listen to those other bozos.

Ken Grooms
24-Oct-2006, 19:04
I want to take this picture with a 4x5 view camera:http://www.photo.net/photodb/photo?photo_id=5055800

I used a 75mm (35mm film equivalent) lens. What lens do I need - 250mm?

Donald Qualls
24-Oct-2006, 19:12
Seriously -- read a book about large format.

That photo could be taken with any lens that will focus close enough on the available bellows, on most 4x5 cameras -- but you'd be focusing to around 1:2 (film image half the size of subject), which, with limited bellows travel, is easier with a short focal length lens than a long one. With my lenses and the limited bellows of my Speed Graphic, I'd reach for the 135 mm or 105 mm for a shot like that, rather than using the 150 mm or its 265 mm converted length, because I wouldn't be able to focus closely enough with the longer lenses (well, probably still could with the 150 mm).

In an image where perspective is important, a 225 mm would be the nearest equivalent of a 75 mm on 24x36, but for this image, perspective doesn't really enter into the equation, since there's no real depth and you don't have to worry about (for instance) making someone's nose look huge by getting too close with a short lens.

Ken Grooms
24-Oct-2006, 19:17
Looks like you're ahead of the curve, Frank - this is only my third question! BTW, I ordered a couple of books, but they won't arrive until Thursday. I need to order the equipment by the weekend or early next week to shoot the foliage. Thanks.
Ken

Ken Grooms
24-Oct-2006, 19:23
Perfect - thanks. I just ordered two books. I want to get the equipment ordered by next week, or else I risk missing my maple tree!

Louie Powell
24-Oct-2006, 19:32
Ken -

The problem is a bit more complicated that merely choosing the lens.

There are two challenges involved in photographing a subject like this with a view camera. The first is that you need to be able to focus rather closely. As you are probably aware from your 35mm experience, to focus closely, you need to move the lens further away from the film plane. In 35mm, that is often done using extension tubes, or perhaps closeup bellows. Or you can use a 'macro lens' which is a lens that has a helicoid mount that enables the lens elements to be racked further away from the film plane than standard lenses. Remember that to create an image on the film that is the exact size of the subject, you need to extend the lens by its focal length. Hence, if you are using a 75mm lens (in 35mm) you need to have 75mm of extension to be able to focus down to 1:1.

Same principle appies in large format. The difference is that the extension comes from the camera bellows, and the longer the focal length of the lens, the longer the bellows must extend to enable you to focus down to 1:1.

Second concern is working distance. To put the problem in perspective, most macro work in the 35mm format is done using slightly longer than normal focal length lenses. The reason for this is that if you have a shorter lens, the camera will be physically closer to the subject when you focus at 1:1. In your example, you mentioned that you used a 75mm lens to enable you to focus closely without having the camera and lens actually in the subject - a 'slightly long' lens in the 35mm format where 'normal' is 50mm.

Again, the same principle applies in LF. You definitely DON'T want to use a "wide angle" lens because if you did, the lens would be right on top of the subject when you rack out the bellows to achieve the 1:1 (or whatever) macro focus you are looking for. Instead, you would want a lens that is at least "normal" for the 4x5 format (assuming you are using a 4x5 camera), or perhaps slightly longer.

Normal in 4x5 is about 150mm. You didn't mention which camera you are using. LF cameras are designed for specific bellows - and bellows are generally not interchangeable. If you chooose a camera with a longer bellows (such as a Zone VI Lightweight), you will be able to use a longer focal length lens to focus on a small subject in the 1:1 macro range. A suitable lens might be 210mm - long enough and yet less expensive that the less common 240 or 250mm lens.

By contrast, other cameras are designed for shorter bellows. For those, you might want to choose a shorter lens (185mm perhaps) so that you can focus closer with the limited bellows on the camera.

In either case, you could probably frame down to 1:1, but the camera with the longer bellows and longer focal length lens will do so with more space between the lens and the subject, and that gives you maneuvering room to deal with lighting and other framing factors.

So you see that if you are looking to do close focus work, the choice of lens is highly dependent on which camera you plan to use it with, or more exactly, on the bellows length that is available with that camera.

Ken Grooms
24-Oct-2006, 20:22
Wow - great explanation, Louie - thanks!

Can you recommend a camera for a 150mm lens to shoot a close-up of leaves? Someone suggested a heavy monorail like a Sinar F.

Frank Petronio
25-Oct-2006, 00:59
Kem, I don't mean to discourage you at all, and people here are generous (or crazy) enough to expound thousands of words on the most mudane subjects. But if this is indicative of your current knowledge of large format, then you most likely have jillion other equally "out of the blue" questions. People are patient here and it gives them something to write about I guess... but buying Steve Simmons' or Jim Stone's book will fast track you compared to the pace of asking one question at a time.

FWIW though, since I am a geek, the reply about the camera's bellows being fixed is tru if you are talking about many of the small folding 4x5 cameras -- Crown Graphics, Wista Fields, most of the wooden and "field" cameras, etc. But most of the monorails are "system" cameras that allow you to interchange bellows and monorails (and many other parts) to build the type of camera you need for whatever shot and lens you want to do.

And, if you impatient, you could recreate your leaf photo with a "heavy" Sinar F with the normal 12-inch bellows and a "normal" 150mm "big-brand" (Schneider, Fuji, Nikon, and yes, Rodenstock!) lens. The Sinar F isn't that heavy, but it is bulkier than a little field camera. However it is more solid and expandable. There are literally hundreds of threads discussing the trade-offs between cameras, but if you can't wait and find a nice deal on an outfit -- with film holders and all the goodies -- then just get one and start experimenting as you read your books.

Open the film box in the DARK!

Ron Marshall
25-Oct-2006, 05:38
Wow - great explanation, Louie - thanks!

Can you recommend a camera for a 150mm lens to shoot a close-up of leaves? Someone suggested a heavy monorail like a Sinar F.

A Sinar F is great for macro because you can screw on additional sections of rail and attach additional standards, so that another length of bellows may be added. I can shoot 1:1 with my 450mm if I want, but I never have because the bellows would be a sail at such an extension.

Most people here are patient with beginner questions. At least they were when I was asking them. Better to ask and get started now.

Leonard Evens
25-Oct-2006, 06:02
You have gotten good advice, including an admonition to read a book or two on the subject before jumping in.

But let me address one further point. The picture you linked to, taken with your Nikon D200, has a 2:3 aspect ratio. The 4 x 5 frame has close to a 4:5 aspect ratio. So to get exactly the same picture, you would need to crop your 4 x 5 image in the short dimension. Of course, you probably didn't mean that you want exactly the same picture, but I thought I would mention it. Also, you apparently were using a multiplier of 3 1/3 to get from 75 mm in 35 mm to 250 mm in 4 x 5. Since the aspect ratios are different, the multiplier depends on which dimensions you compare. 3 1/3 comes from comparing the long dimensions (120 mm over 36 mm), which might be a plausible choice. In any case, as several people explained, for a relatively flat subject, like that in your picture, the focal length is not particularly relevant. You would get essentially the same picture from many different focal lengths. But, since the picture is close-up, you would want to choose a relatively longer focal length to have a reasonable working distance.

Ole Tjugen
25-Oct-2006, 07:05
Here's a "reverse" way of thinking about it:

For shooting things flat on the ground (or floor), you want to be able to look in the ground glass in some comfort. How high that is, depends on your own height - I'm 193cm, so the highest "comfortable height of the ground glass" for me is about 160cm. The lowest is about 80cm, or I'll be too close to the subject.

Now the closest you can get the ground glass to the subject is at 1:1. At that scale, the distance from GG to subject will be (very close to) 4x the focal length. So I don't want to use lenses shorter than 200mm for this. A 200mm lens with the GG at 160cm gets you far enough from the subject that you will need some kind of ceiling support to avoid getting the legs of the stand in the frame, so that's not a problem. Also, since 1.60m allows 1:1 with a 400mm lens those are my limits: A focal length between 200mm and 400mm works fine. My personal preference is a 240mm Symmar, which not only has exellent close-up capabilities but also covers all the formats I use at these distances.

C. D. Keth
25-Oct-2006, 08:06
Ole, you always have such a strange though very effective way of looking at things. Thank you! :)

Kevin Crisp
25-Oct-2006, 08:28
Ken: Are you aware that for close ups you will have to make an exposure adjustment based on how far you extend the bellows? Not hard to do, and there is a nifty disc system on the web that makes it easy, but if you just meter and get really close and don't compensate for how far out there the lens is, you will get underexposed film. It is best not to discover this effect for yourself.

Brent McSharry
25-Oct-2006, 09:03
Frank Petronio
Open the film box in the DARK!

had a great chuckle at this parting bit of advice. I hadn't thought of this before but definately the single most important beginner advice I have ever read!

Ken obviously you have to come up with your own ideas, but FWIW:

Like any skill, only those with experience can afford to rush LF (and like you I am definately a beginner).

I would advise being happy with digital captures for this autumn (fall). It will come around again. take your time to work out the right equipment and focal lengths, and buy without this sense of rush.

Once you have your equipment, then take even more time to consider focal length composition, lighting and exposure (including exposure compensation for bellows factor). Practice setting different compositions. If what you see on the groundglass isn't quite right, or the light not what you were after, try a different composition, or wait for the right light - every camera setup is good practice.

If you are like me you will still get things a little wrong, but with enough of an image recorded to work out how to tweak things next time to get a truly professional quality image. If you rush in at the moment, I suspect many negatives/positives will be ruined and autumn will be long gone.

Enthusiasm is great, and LF photography really rewarding, but high quality LF equipment and film is expensive, and an unwise choise could be a great waste of money.

good luck and enjoy

Frank Petronio
25-Oct-2006, 09:36
One more bit -- Consider taking a workshop where you can see people in action. If you aren't a book learner, seeing people using large format first hand is so much more powerful.

Most of the older, white, upper-middle class, technically-educated, bearded men who participate in these workshops (let's be honest here ;) ) are also into nature photography. (Pipe smoking is optional.)

There are all kinds of workshops, from free to luxury expeditions. Sometimes the free ones are more valuable.

Brian Ellis
25-Oct-2006, 09:49
I'm not sure I fully understand the question and when I saw the tone of some of the responses I didn't bother reading the rest so if this is repetitive or isn't the answer you were looking for, my apologies. But FWIW, you can get an approximate 35mm >4x5 lens equivalent by multiplying the 35mm length by 3.5. So the 4x5 lens that's approximately equivalent to a 75mm lens is 260mm. You could round down to 240 or up to 300 for two commonly available 4x5 lengths. Of course there isn't an absolute equivalent between 35mm and 4x5 because of the different aspect ratios of the two formats.

Ken Grooms
25-Oct-2006, 18:45
Ken: Are you aware that for close ups you will have to make an exposure adjustment based on how far you extend the bellows? Not hard to do, and there is a nifty disc system on the web that makes it easy, but if you just meter and get really close and don't compensate for how far out there the lens is, you will get underexposed film. It is best not to discover this effect for yourself.

http://www.salzgeber.at/disc/disc.pdf

Thanks! :)

Kevin Crisp
25-Oct-2006, 19:35
Thanks for adding that link, Ken. It is pretty slick!