Need some help please!

[carlosmh1910]

Ok, here is my question (it is a bit lengthy, sorry.)

I've been shooting straight down at the ground because I like the textures, but I've run into some problems.

1) I was using a 150mm Nikon and a 210mm Caltar, and the results are ok, but I would like to zoom in more and get more details. I know the closer I get to my subject and the longer the focal length, the more bellows I'll need, but I'm worried that if I buy a 310mm lens that the subject to film ratio will be outside of the lenses optimum range. It will basically be macro work, but I don't have the money to spend a 1,000 or more on a crazy macro lens. Any ideas?

2) With the 210, I'm getting pretty good details, but when I'm printing (at 24x30ish) the details are not as great as I expected. Am I losing details in the scanning process perhaps? I'm using a flextight X1, but for some reason the max dpi in the flexcolor program will only allow me to go up to 300 dpi, but on tutorial videos for flexcolor, I saw somebody go up to 8000?

3) I've been shooting at f16, but my depth of field is still pretty shallow. I've been using a bubble level to even the film plain to the ground, but I'm afraid to stop down to much in fear of resolution because the whole idea of the project is to make HUGE prints (like 40x50.) My question is, can I use a larger zoom like 310mm, which is not optimized for 2:1 or 1:1 and stop down, while still getting quality images?

Thanks for reading, I REALLLLLY appreciate any help, thanks!

Here is an example of what I'm doing.
69314

[carlosmh1910]

Ok, I have a lot of views but nobody has an answer? So, here is a simple question maybe someone can answer. Would it be better to buy a longer lens (300 or so) to zoom in or just move the shorter (210) lens closer to the ground? Which one would give me greater depth of field?

[Brian C. Miller]

Yeah, Frank, don't you have an answer??? ;)

Ok. The "problem" with a "non-optimized" lens is that beyond 1:1 the red, green, and blue parts don't line up on the film. You can see that in various web pages about macro photography, where there's a bit of red and blue fringe. You are shooting black & white, so you can simply put a filter over the lens, and just remove that part of the spectrum. Since the other parts of the spectrum aren't there to be a problem, the image will be sharp. If you were shooting color, then an optimized macro lens would be required.

Depth of field is determined by f/stop and focal length. The longer lens will require you to stop down more, and that's all there is to it. Also, depending on what you want to do, you'll have to raise your camera up higher, and maybe you'll have to buy a taller tripod to compensate for the longer lens.

If you want more details, then just use more extension. However, your photograph has a really good balance to it as it is, and that's the most important thing.

If you absolutely must have more extension then you must use a shorter lens to give you greater magnification. (Unless you have lots of bellows extension.)

[Lachlan 717]

Carlos,

A couple of things:

First, have you looked at DOF charts for your focal lengths? Looking at DOF of lenses at specific focal distances will give yo a good idea on how much "play" you have at any given f-stop. Also, when using DOF, remember the basic one third forward/two thirds back theory; this will maximise your range.

Second, have you looked at lenses such as the G-Claron 240mm or 270mm G Clarons or a Fujinon 240mm A? These are going to be good at these close ranges.

Finally, if you need more bellow draw, consider a top hat extender. As you're shooting parallel planes, these will be easy to use.

Keep us updated!

[l2oBiN]

I would also suggest a process lens but of a shorter focal lengh..

For example the tominions can be cheap .. 75mm or 100mm..

You should be able to find them in copal press shutters..

[carlosmh1910]

Thanks everyone for your insightful responses. This forum always seems to help when I need it most.

The info about the DOF charts are very helpful! When I started the project, it was digital, and when I wanted to make the prints bigger I switched to LF. I had no idea the technical side of things would be so difficult for such a seemingly simple idea. Some of the technical aspects are still very confusing to me.

"You are shooting black & white, so you can simply put a filter over the lens" Brain, the picture looks black and white, but it's actually color. I shoot color, scan the negative, and desaturate (among other things) in photoshop to make all of the prints look cohesive. Thanks for the info, now I know I have to get an optimized lens.

Lachlan,
I've looked at a G-Claron 305mm, and the person is asking $400, is that fair? I heard that it was more optimized for macro work, is that true?

[Doremus Scudder]

Carlos,

If I understand your problem correctly, you aren't satisfied with the amount of detail you get when using your 150 and 210mm lenses. I'm assuming that your desire for a longer lens means you want to photographs a smaller portion of the ground.

So, my question back to you is: Why don't you just move your camera closer to the ground and use the lenses you already have? Have you tried that and were not satisfied? If not, you should. Using the 150mm closer and keeping to optimum f-stops (f/16-32) should give you pretty good results, even though the lens is not "optimized" for that distance.

And, I wouldn't hesitate to shoot at f/22 or f/32 if you need the depth-of-field. Those are the best stops for most LF lenses. I shoot table-tops and close ups with a 135mm Nikkor and get really sharp results, even when I have to stop down to f/45. Admittedly, I don't enlarge to 30x40, but at 16x20 things look really sharp, and should take another 2x enlargement. For me, better diffraction than out-of-focus.

Moving up to a longer lens will just give you more depth-of-field problems. A 300mm lens has a really shallow depth-of-field, and you'll have to stop down well into diffraction range to get anything but a flat subject in focus close up.

Maybe, as you imply, your scanner is the weak link in the chain. I'd examine the negatives under a good loupe, or even microscope to see if they have the detail you want.

Hope this helps,

Doremus

[carlosmh1910]

Thanks for all of the good advice. With the combined information you guys have given me, I think I'm going to get a G-Claron 210mm and if I need closer shots, I'll just get another rail extension (because I've already got an extra set of bellows.) I'll keep you updated on my progress and upload a pic when I get it done. It may be a week or two though because I've got an Organic chemistry exam coming up, and that takes up most of my free time:( Again, thanks everyone!

[Paul Fitzgerald]

"I've been shooting straight down at the ground because I like the textures, but I've run into some problems."

"2) With the 210, I'm getting pretty good details, but when I'm printing (at 24x30ish) the details are not as great as I expected. Am I losing details in the scanning process perhaps?"

Most lenses are actually sharper than film can resolve.

Sheet film bows out and could be going 'out of focus' when shot straight down.
It also bows out when you pull the dark slide and it hits higher humidity in the bellows.
Vacumn film holders are available but expensive.

You could try a strip of double-sided tape in the holder but do run a rag over it after it's installed to soften the grip of the tape.

You should also do a focus test at the distances you are using with those holders.

[carlosmh1910]

Several of you mentioned bringing a shorter lens closer to the ground (150mm or shorter?) instead of a longer 210mm because of DOF. Does anyone know how to calculate this or where I can find the calculations? I know I ask a lot of questions, because I'm still very much so a beginner. I only have money for one lens, so I want to make the right decision. I've already sold off half my possessions for equipment and film, haha.

I've been shooting a lot of film and found that for certain shots, I would really like to photograph a small area 2 or three inches across that is fairly flat. I've got 35 inches of bellows extension to work with, and I'm not partial to any focal length really. Unfortunately, I don't know the calculations to find out what focal length will give me the most play in DOF, or if the difference between 150mm and 210mm in DOF is really that big of a deal at all (or even shorter?). This may seem very noobish, but I know when I shot digital, there was a "minimum focus distance." Is this the case with a shorter lens if I bring it really close to the ground to magnify? Or was the minimum focus distance only a problem because digital does not have the ability to move the film from the lens?

Again, thanks. You guys have no idea how much easier you're making my life, because large format info seems hard to come by these days.

PS. I've looked this link http://www.largeformatphotography.info/articles/DoFinDepth.pdf and even though I've taken college physics, it still confused me. There are a lot of articles that try to calculate the best f stop, but I can't seem to find a calculation pertaining to macro work to figure out how much DOF I'm working with at different focal lengths.

[carlosmh1910]

After scouring the internet, I've read mostly for macro work the focal length is of little consequence anyway.

[Leonard Evens]

Carlos,

A couple of things:

First, have you looked at DOF charts for your focal lengths? Looking at DOF of lenses at specific focal distances will give yo a good idea on how much "play" you have at any given f-stop. Also, when using DOF, remember the basic one third forward/two thirds back theory; this will maximise your range.

Second, have you looked at lenses such as the G-Claron 240mm or 270mm G Clarons or a Fujinon 240mm A? These are going to be good at these close ranges.

Finally, if you need more bellow draw, consider a top hat extender. As you're shooting parallel planes, these will be easy to use.

Keep us updated!

The one third front DOF, tiw thirds back DOF works only at one distance the hyperfocal distance divided by three. It may work approximately for moderately short distances, but it works neither for close-ups nor for distant subjects. In the former case, close-ups, the near DOF and the far DOF are approximately the same. If you focus at the hyperfocal distance, the far DOF is infinite, which is much larger than twice the near DOF.

[Bill L.]

Before you spend any more money on gear. . .

My understanding is that dof is based on focal length, f-stop, and focus distance. And that for the same film format, the dof is the same if the object magnification is the same, I.e. If you compose the exact same scene with a 150 or a 300, at the same f-stop, the dof will be the same. This of course does not apply across format, so the same scene with a 50mm on a 35mm camera will have greater dof than the equivalent scene on a 150mm on a 4x5. So, if you are shooting the same area with your 150 as you are with a 300, you will get the same dof at the same f-stop, since you have to get closer with the 150 to get the same magnification. Optics experts, feel free to correct me on this. All this to say, why don't you try your 150 closer to your object, since you most likely will have the bellows capacity, and see if you like the results before being new lens and rails.

From the softness standpoint I agree with the film flatness comment above, but also am concerned about the scanning. If you are only scanning at 300 dpi on 4x5, you're printing 24x30 at 50 ppi, which would make a soft print. I don't know the flextight scanners enough to comment other than they are capable of much more than 300 dpi scanning.

Good luck, and the first teaserr shot looks like this will be an interesting project.

Cheers!
Bill

[Ole Tjugen]

Lots of good advice here, but consider this:

From what I can see, you are close to the "macro range" here. That means that focal length won't affect DoF, since the reproduction scale is what you frame for - and at the same reproduction scale, DoF is independent of focal length.

Most LF lenses are optimised for :10 or 1:20; macro lenses are optimised for 1:1. It looks to me as if you're somewhere between those, and as far as I know there is only one lens (or set of lenses) optimised for 1:3 : The old convertible Schneider Symmar.

They are surprisingly good, and with the exception of the 150mm the cells can easily be swapped for very close macro, at 3:1.

Also, don't worry about diffraction: In your setup the DoF is the limiting factor even at f:32.

[pdmoylan]

This is a classic case of misstatements concerning DOF. I would have expected better from our team of LF experts.

DOF is not determined by the focal length at all, but by the magnification and Fstop period.

So at 1:1, and f45, any lens you use will give you the same distance of focus in front of and behind the subject. The only exception to this rule is when wide angles reach infinity sooner then longer lenses, but this is for landscape work.
That said, to maximize DOF for landscape work you need to incorporate hyperfocal focusing.

I suggest the Nikkor 210mm AM lens which is optimized for what you are trying to accomplish. It is overkill as to coverage but the images at 1:1 are stunning.

[John Olsen]

I've used lenses from my enlarger for that with a temporary cardboard lensboard. Those lenses are designed for magnification. Think of the ground as film in an enlarger. If you're outdoors, the problem will be to find something to use as a shutter. In a studio you'd just use the lights themselves. Good luck.

[carlosmh1910]

I've been practicing while my lens is in the mail and I've run into some issues about exposure.

I'm aware that the effective f stop = (f-stop) (1+ magnification) So I have to compensate my exposure, but my question is, do I still have to compensate for bellows extension as well? Or does that fix the exposure already? Thanks for your patience guys! I appreciate it.

So if I've at 1:1 and I'm stopped down to f22, my effective f-stop would be 44? My bellows would extension would be about 18 inches at 1:1 because I'm using a 210mm lens.

Carlos

[PhotoToyo]

If I saw some screen shots of your settings in FlexColor for your X1 scans, I may be able to decipher the problem with resolution capping out at 300dpi. You should definitely be getting more out of that scanner (it has a max optical resolution of 2040dpi for 4x5" films). Screen shots of the Setup window (File>Setup>General Tab) and of the main window of FlexColor (with all the options on the left) might help.

[Jack Dahlgren]

I've been practicing while my lens is in the mail and I've run into some issues about exposure.

I'm aware that the effective f stop = (f-stop) (1+ magnification) So I have to compensate my exposure, but my question is, do I still have to compensate for bellows extension as well? Or does that fix the exposure already? Thanks for your patience guys! I appreciate it.

So if I've at 1:1 and I'm stopped down to f22, my effective f-stop would be 44? My bellows would extension would be about 18 inches at 1:1 because I'm using a 210mm lens.

Carlos

Effective f stop as you calculated is based on extension so it is the same as bellows extension. Using both would be double counting.