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View Full Version : 150 or 240 for 4x5 closeup work?



Jonathan Lee
14-Nov-2003, 07:54
I am planning to do a series of close-ups in 4x5 (1:5 up to 1:1) and I am trying to choose a convenient focal length for my Ebony RW45. My Ebony has a spec bellows extension of 430mm, so I beleive that even with a 240, I should be able to get close to 1:1. My major concern is working distance. My only lens is a 90mm so I can't make an estimate of working distance myself. The subjects will be placed on the ground and photographed from above. With my current tripod setup, this will mean that I can work no more than 5.5 feet above the subject. Is 240 too long for 1:5 work with this setup? Alternatively, is there a formula to estimate working distance as a function of focal length and magnification?

Thanks

Jonathan

Mark_3632
14-Nov-2003, 08:19
I do not get a lot of working room with my 150. I do not have a 240 (someday I hope) so i cannot comment on that. The 150 is pretty cramped and out side because of the closeness the shadow of the camera has to be taken into account. A bit more distance and this might not be a problem.

I would go for the 240

Just a thought

Ernest Purdum
14-Nov-2003, 08:51
At 1:1, you need two focal lengths of extension and your subject will be two focal lengths from the lens. At that distance, you can't focus by moving the lens, you'll just be changing the image/subject ratio. You need to move either the whole camerqa or the subject. A "laboratory jack" (frequently available on eBay) is a convenient way to move the subject.

Ryan M
14-Nov-2003, 08:51
Johnathan, Before I sold my Ebony, I used a cool extention lens board that you can screw multiple extention tubes onto. I used to get closer extention with a 305 G-claron. I got mine from badgergraphic.com. Using this should let you use the 240 with the RW for close-ups with ease.

Steve Hamley
14-Nov-2003, 09:03
Johnathan,

I have used both on a 4x5, but the 240mm suffers from depth of field problems for "deep" subjects near 1:1 that the 150 does not. For general use, I prefer the 150.

Thanks!

Steve

John O'Connell
14-Nov-2003, 09:23
A) The 240 can't get to 1:1 on your camera. I want one myself, but as an 8x10 macro lens.

B) At 1:1, the 150 will eat up 300mm of your camera's extension. That means you'll still have 130mm of extension to play with if you go with the 150. A very useful 130mm...

If your camera allows focus adjustments on the back standard you can use the additional extension as a focusing rail. The additional extension will also allow your bellows to flex enough to apply movements (shift & rise are quite handy in macro).

At full extension, no camera is any fun. Your bellows tend to be as tight as a drum, and a #3 shutter on a teeny-weenie 4x5 camera stretched out half a meter doesn't inspire a lot of confidence.

Lighting can be tricky with a 150: get a good reflector. It doesn't have to be big, just packable and efficient.

I recommend the 150. I think you'll find yourself working slightly beyond 1:1 quite often, and you'll be thankful that you have the flexibility.

Michael S. Briggs
14-Nov-2003, 10:55
The equations for calculating image-to-lens distance Si and lens-to-object So distance are in the Lens Tutorial by David Jacobson at http://www.photo.net/learn/optics/lensTutorial.
As others have said, the case M=1 gives both Si = 2f and So = 2f. For 1:5 (M=0.2) and f=240 mm, the lens-to-object distance would be So = 1440 mm = 1.44 m = 4.7 feet.





I used a 240 mm lens for studio type shots at 1:few and found the distances to be inconveniently large for the room I was using. If you have a sizeable studio it would work well. I don't think you will find 1:few to be convenient with a 240 mm lens with the camera pointing down to the floor. You will need a ladder to view the ground glass in this configuration. Both Rodenstock and Schneider make 180 mm macro lenses, which is a clue to what focal length either the manufacturers or the market demand thinks is good. I think 180 mm is a good compromise between having enough coverage (which wants a long focal length) and not consuming too much space or bellows extensions (which wants a short focal length).

Dave Schneider
14-Nov-2003, 11:24
The depth of field at 1:1 magnification will be the same with either the 240 or 150mm lens. The only thing that will change is the working distance. I have used both the 150 and 240 for applications in this magnification range and find the 240 is preferable. The increased working distance is a definite advantage for dealing with the lights. I don't have a limitation with bellows length, if you do the 240 may not be convenient.

Ted Harris
14-Nov-2003, 17:59
I do a lot of work with small objects in the range you are discussing. I use lenses ranging from 235mm to 360 mm but find that I work with 180 mm most frequently.

Guy Tal
15-Nov-2003, 06:49
A few considerations for macro work:

* Longer focal lengths result in shallower DOF
* Longer bellows requirements result in a setup that's more prone to vibration

I do a fair amount of close-up work with my 150 - I consider it a great tool for the job in general. However, the two considerations above often make 120 more desirable when large magnification is required (it's no accident so many manufacturers have optimized macro lenses in this focal length).
For 1:5 you may be more comfortable with a 150 or 180 in terms of working distance.

Guy

Dave Schneider
15-Nov-2003, 13:44
OK,it's been repeated twice in this thread, someone explain it to me. If I have the same magnification ratio, 1:1 example, why does the depth of field change with the focal length? Using Bob Wheeler's Vade Mecum (which I always use when shooting and have these questions) I get the exact same depth of field at 1:1 with either the 150mm or 240mm focal length. Now is Mr Wheeler's program in error or are the posters in this forum just guessing?

Dan Fromm
15-Nov-2003, 14:59
Dave Schneider asked "are the posters in this forum just guessing?"

A rhetorical question, without doubt.

According to Cox, "The hyperfocal distance has this property: if a lens is focused on the hyperfocal distance, then the depth of field extends from infinity down to half the hyperfocal distance." In my copy of Photographic Optics, printed 1971, the text quoted is on p. 70.

Further on, Cox added "The hyperfocal distance is not something definite for a lens alone. It is definite only for a lens at a particular aperture (in italics for emphasis), and changes as the lens is stopped down." He goes on to present formulas for depth of field which contain, among other things, the diameter of the circle of confusion.

Bulletin boards attract bullshitters like shit attracts flies and, not to overlook their important role in nature, dung beetles.

Now will you all please shut up and go back to taking pictures?

Cheers,

Dan

Dan Fromm
15-Nov-2003, 15:11
Oh, crap! Posted the right reply in the wrong thread.

Dave, for all practical purposes aperture and magnification control depth of field. Same aperture, same magnifiction, same d.o.f. regardless of lens' focal length. I've tested this idea informally on 35 mm with a 55 and 105 MicroNikkors and a Questar 700, all at f/8 and 1:2. The slides (KM, flash illumination, one stop more for the Questar) were indistinguishable.

There is one situation where this rule can be beat a little. At normal working distances, e.g., inside a large room, suppose one uses a short lens rather than a long one from the same position and then prints the two negatives to the same size, cropping the shot with the short lens so it covers the same field as the negative shot with the long lens. In this case, the short lens can give a print with more d.o.f than the long one.

Focal length and magnification control film-to-subject distance. At the same magnification, the film is closer to the subject with a short lens than with a long lens.

What confuses the hell out of many people is the situation in out-and-about photography where one changes focal length without changing film-to-subject distance. In this case magnification is lower, and d.o.f. greater, with the shorter lens. So shorter lenses give more d.o.f. QED. Yeah, but because of working at lower magnification.

Cheers,

Dan

Dave Schneider
15-Nov-2003, 15:50
Thanks Dan. That's what I thought. So the repeated posts here that when doing doing macro work you get more DOF with the shorter focal length are incorrect. You will have the same DOF with either lens, provided that you are maintaing the same magnification or image size. I thought so.

Mark Sampson
17-Nov-2003, 12:01
One thing to think about, assuming you're not copying flat art, is perspective. The 240 is 'long' for 4x5, the 150 is 'normal'. The 240 will tend to flatten the image out, the 150 will make the subject appear 'rounder' or more 3-dimensional. And you can use your 90mm as a macro lens, if you don't mind the subject being 1/2 inch from the front element...

Dan Fromm
17-Nov-2003, 12:33
Mark Sampson suggested "And you can use your 90mm as a macro lens, if you don't mind the subject being 1/2 inch from the front element..."

Mark, forgive me for being a literal minded imbecile. Were you joking? The minimum front node to subject distance is 2f. My 100/6.3 Neupolar's front node can't be more than .25 f behind the front of the front element, and I suspect other LF macro lenses are much the same. 1/2 inch, indeed!

Cheers,

Dan

Dan Fromm
17-Nov-2003, 14:52
Make that a sloppy literal minded imbecile. Minimum front node to subject distance to subject is f, not 2f as I typed earlier today. The argument stands, though.

Sorry,

Dan