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lxdude
01-01-2011, 11:38 PM
I said that 24mm was approximately 1 inch. Actually 24mm would not let the edges of the sphere show. By making the approximation and then using that image size, I was eliminating the format size from the question.

'dude, you gotta start drinkin' later in the day. :laugh:

Steve
Hey, you asked for it! :laugh:

David A. Goldfarb
01-01-2011, 11:44 PM
A lot may depend on factors like the lenses you actually have in hand for the formats you are shooting, and I wouldn't discount grain as a factor in what the final print is going to look like.

One thing to be aware of, if you've got a really good macro lens for 35mm is that it will cover larger formats at larger magnification, if you can find a way to mount it physically to the camera. At the same time, it may be the case that the lens is better optimized for the magnification ratios likely encountered with the primary format than with the format the lens has been adapted to (say 1x-5x on 35mm could be better than 8x-40x on 8x10").

Just run some tests and make some prints with what you have, and you'll see what you like. When I've had a particular macro project, that's what I've done, trying different lenses, reversed lenses, enlarging lenses, etc. at different reproduction ratios, and seeing what works. If you have a real macro lens for 35mm, it may look better than a non-macro lens for 4x5", at macro magnifications. You may find, for instance, that a lens that isn't a dedicated macro lens for the magnification ratio at hand introduces an unexpected distortion or an internal reflection or flare (adequately shading a reversed lens can be tricky) that produces a hot spot, negating any other advantage of the lens.

Q.G.
01-02-2011, 04:40 AM
Exactly. But, you will have to enlarge the 4x5 sheet 1/4 as much as the 35mm! So does it all cancel out? Does shooting at 4:1 then contact printing have any advantage over shooting at 1:1 and enlarging 4x?

People talk like shooting to smaller magnification and enlarging is better than shooting at larger magnification then enlarging less. At least that's the way it seems because they always advocate 35mm for macro applications and say leave the view camera at home. Landscape, it's exactly the opposite, both for supposed image quality reasons.

It does indeed cancel out. That is: except the better detail and less obvious 'film artifacts' you get when you record a larger image on film that is subsequently enlarged less.
So yes, shooting at larger magnifications is better (but - depending on the difference in film format, of course - only marginally).

It means, however, you have to use more difficult to handle larger format equipment.
And that's what behind the advice to use 35 mm format.

But it is a clash of the two approaches i mentioned before: the first is the compositional/format driven one, which comes with the benefit of better image quality when you step up in format. The second is the magnification driven approach, in which (as long as the subject fits in the format at the desired magnification) favours the smaller format (for greater ease of use with the same image quality).
So what to do is something that has to be decided on a case by case basis.

On top of that, you get all those considerations David mentioned.

hpulley
01-02-2011, 05:57 AM
Exactly. But, you will have to enlarge the 4x5 sheet 1/4 as much as the 35mm! So does it all cancel out? Does shooting at 4:1 then contact printing have any advantage over shooting at 1:1 and enlarging 4x?

People talk like shooting to smaller magnification and enlarging is better than shooting at larger magnification then enlarging less. At least that's the way it seems because they always advocate 35mm for macro applications and say leave the view camera at home. Landscape, it's exactly the opposite, both for supposed image quality reasons.

Assuming good lenses and film, a two, four or eight times lifesize image will contain more detail than a lifesize image. The only catch here is the depth of field and diffraction effects. This affects landscapes and portraits as well but I think the extreme DOF at close focus distances makes the problem worse for that work than for landscapes.

I'm trying to think if you'll have 8x narrower DOF at 8:1 or more than that. If it is 8x narrower will it be less obvious in a contact print than the required 8x enlargement of a 1:1 image? Is there a nonlinear factor which won't come out in the wash?

Grain and tonality will be better on the larger piece of film. If the other factors can be practically overcome then the larger format should win but can you buy or make an 8:1 setup for an 8x10 camera?

Q.G.
01-02-2011, 06:03 AM
I'm trying to think if you'll have 8x narrower DOF at 8:1 or more than that. If it is 8x narrower will it be less obvious in a contact print than the required 8x enlargement of a 1:1 image? Is there a nonlinear factor which won't come out in the wash?

If the final magnification is the same, DoF is too.

There isn't enough DoF anyway, so an 8x reduction of it may sound pretty impressive, 1/8th of nothing isn't significantly less.
;)


Grain and tonality will be better on the larger piece of film. If the other factors can be practically overcome then the larger format should win but can you buy or make an 8:1 setup for an 8x10 camera?

Yes, you can. You just don't use a 210 mm lens. ;)

You typically use very short lenses (i use 16 and 25 mm lenses mostly) when in-camera magnification gets beyond 3 or 4x life-size.

It's not just grain and tonality, but also that - because of the larger in-camera magnification - you resolve more subject detail. Enlarging an image recorded on a bit of film will not increase the amount of detail you see in the subject, just enlarges what you have captured on it at that lower magnification. Get to the same size magnification on film, and there will be more detail in the captured image.

hpulley
01-02-2011, 07:20 AM
May just have been 35mm defenders but the old adage was always that 8x10 lenses didn't need to be that sharp as they weren't enlarged 10-20x on printing like 35mm needed to be for anything more than the 4x6" snapshot developing plus prints option at the lab.

Which 16 and 25mm lenses cover 8x10" sheets and have good close focus characteristics?

Q.G.
01-02-2011, 07:35 AM
Zeiss Luminars, Olympus bellow head lenses (they were/are 20 mm and 38 mm in focal length), Leitz Photar lenses. I'm sure Nikon and others make the same type 'micro'-lenses as well.

Mind you, they only cover large formats at high(ish) magnifications. But then, that's what they are made for.

Different focal lengths are not chosen to get a different field of view, but are optimized for different magnifications (or rather, ranges of magnifications), so are chosen to match the magnification you're after.
As a rule, the higher the magnification you are after, the shorter the lens that's best suited. (For instance: the 16 mm Zeiss Luminar is best for 10 - 40 x, for a bit less, 6 - 25 x, the 25 mm Luminar would be better.)

hpulley
01-02-2011, 07:54 AM
Same as enlarger lenses. Thanks.

Diapositivo
01-02-2011, 08:39 AM
Well, just to split my half hair, if the spheric seed is opaque, you cannot see from any angle more than half of it, so you only need half inch of depth of field :whistling:

The question of the OP I think can be generalized beyond the macro field. If you use a 200 mm lens, on whichever camera, to take a shot of a landscape, and there is a certain bell tower in this landscape, the absolute size of the bell tower on the film will be the same regardless of the dimension of the photogram. On an APS, 135, 120, or LF film, given a certain focal lenght, the dimension of the object is the same, and the DOF is the same.

We have the "impression" 200mm is more a tele in a small format because we don't get, and don't print, all what would have been "around" the bell tower.

So if you use a 200 mm with a 4"x5" and with a 135, if you only print a 24x36 portion of your 4"x5" film, you have the exact same results.

The same applies to macro photography. So, strictly speaking you need a larger format than 24 x 36 only if you need a 1:1 reproduction, on film, of a subject that is "bigger than 24 x 36". (Or you need LF because you need movements and it is easier with LF).

At the end of the day, you can always use LF with movements, take a LF picture, and only print a 24x36 portion of it, but you will have used the Scheimpflug law.

Post #3 seems to suggest that maybe the OP deems that the actual f/value of 44 has an influence on the DOF. If this is the case, I'd like to say that to my (quite imperfect) knowledge, it has not. The light fall caused by extension tubes, bellows, or teleconverters, is not accompanied by a correspondent DOF increase, nor by a correspondent diffraction increase, because DOF and diffraction, as far as I know, depend on diaphragm aperture.

Fabrizio

Q.G.
01-02-2011, 02:13 PM
Same as enlarger lenses. Thanks.

But quite different thingies.

Galah
01-03-2011, 06:39 PM
Recently I have been trying to photograph a small round seed pod at about 1:1 with my Olympus OM1 and 50mm Macro with extension rings. I put the lens on f/22 which is probably an actual f/45 or so at 1:1. The 8x10 proofs I made aren't impressively sharp, and I think I have eliminated camera/subject motion as a cause.

Effective Aperture=Nominal Aperture x (magnification +1)

So, in your case (above) EA=22(1+1)=44 :)

Nathan Potter
02-13-2011, 11:01 PM
The Z stacking is superior but as David points out this is an analogue site, so instead the OP could use a psuedo stacking technique developed long before digital shenanigans. That would be all analogue scanning photomicrography. The idea is simple and obvious but devilishly difficult to execute. The trick is to illuminate the subject with a sheet of light of a thickness equal to approximately the depth of field of the lens while simultaneously focusing the lens at that illuminated sheet. The subject is then moved thru the sheet of light while the shutter is open, exposing the entire subject during its transit thru the plane of best focus and illumination. Since the shutter is open during the extended exposure time (typically 10 to 30 sec.) the room needs to be darkened to avoid extraneous light fogging the film. The key advantage is that if the plane of light can be made as thin as the depth of field of the lens at a moderate aperture - say f/8 or 11 - pretty decent resolution can be realized over a large distance. The subject needs to be translated thru the focus plane at a uniform velocity to avoid banding of the lighting uniformity. One can use either a stepper motor or even gravity thru a dashpot connection for translation. I have done this in a vertical setup with translation in Zaxis and dual slit illuminators horizontally positioned in an X and Y plane. Lots of setup here but it gets the job done with superlative results.

Nate Potter, Austin TX.

Philip Taylor
04-24-2013, 06:16 AM
Ok guys, lets get it right. It's Photomacrography not Macro Photography.

Right, now...since we're on an analog forum....
Forget Z stacking & look up "light scanning photomacrography". Simple.
Yes, you need to find, or build the equipment, but the results can be stunning...especially on LF.

Sorry, should have read the previous post first :D
Nice to see someone else has enjoyed this technique Nate!

E. von Hoegh
04-25-2013, 10:03 AM
Recently I have been trying to photograph a small round seed pod at about 1:1 with my Olympus OM1 and 50mm Macro with extension rings. I put the lens on f/22 which is probably an actual f/45 or so at 1:1. The 8x10 proofs I made aren't impressively sharp, and I think I have eliminated camera/subject motion as a cause.

I use a Nikon 55/3.5 at that ratio quite a bit, and keep the lens at f:4 which means f:8 working aperture. You're working at f:45, and diffraction is giving you mush. Your lens is limited to 33 lp/mm at that stop (assuming the film is recording everything the lens gives it), when you enlarge it to 8x10 that becomes about 4 lp/mm on the print.

polyglot
04-25-2013, 07:02 PM
The Z stacking is superior but as David points out this is an analogue site, so instead the OP could use a psuedo stacking technique developed long before digital shenanigans. That would be all analogue scanning photomicrography. The idea is simple and obvious but devilishly difficult to execute. The trick is to illuminate the subject with a sheet of light of a thickness equal to approximately the depth of field of the lens while simultaneously focusing the lens at that illuminated sheet. The subject is then moved thru the sheet of light while the shutter is open, exposing the entire subject during its transit thru the plane of best focus and illumination. Since the shutter is open during the extended exposure time (typically 10 to 30 sec.) the room needs to be darkened to avoid extraneous light fogging the film. The key advantage is that if the plane of light can be made as thin as the depth of field of the lens at a moderate aperture - say f/8 or 11 - pretty decent resolution can be realized over a large distance. The subject needs to be translated thru the focus plane at a uniform velocity to avoid banding of the lighting uniformity. One can use either a stepper motor or even gravity thru a dashpot connection for translation. I have done this in a vertical setup with translation in Zaxis and dual slit illuminators horizontally positioned in an X and Y plane. Lots of setup here but it gets the job done with superlative results.

Sounds interesting, but I'm slightly confused. Surely if you're moving just the subject (with illumination plane, camera and focal plane all stationary) then you're just going to get a smear unless the shape of the subject is extremely constrained so that no two parts at different depth image onto the same part of the film?

Wouldn't it be more accurate (obviously more difficult) to slide the focal plane and the illumination plane through the subject while keeping the subject/lens distance fixed? It'd mean that the light and film back go in the same direction but at different speeds unless the magnification is 1:1 and doesn't vary much through the depth of the subject.

Philip Taylor
04-26-2013, 05:23 AM
then you're just going to get a smear unless the shape of the subject is extremely constrained so that no two parts at different depth image onto the same part of the film?

You're still making a 2 dimensional image of a 3D object, so as you say, no two parts of the object are exposed onto the same piece of film. If light hits a part of the object underneath another which has already been imaged, the first piece is blocking the now illuminated part (from lens viewpoint), so it is never imaged.

There are some issues with the technique:

Because camera, light sheet (& focus) are all set, and the image is only made at that plane as the object passes through it, magnification is constant, and therefore perspective doesn't work as it normally would. "Leading lines" no longer exist, and objects look a bit flattened.

A sphere would lose it's expected shape, I imagine.

To create a light sheet, often two boards in the shape of a donut are sandwiched 1 or 2mm apart from each other (we used brass spacers), then 3 lights are placed 120deg from each other around the edge, directed into the centre.
This works well, but if the object has holes or depressions in it, they may not be illuminated as it passes through the sheet - the end result is an object with a deep shadow in the said depressions.

But, for a sphere, this isn't an issue.

Not sure if that makes things any clearer or worse.

polyglot
04-26-2013, 06:21 AM
Yeah, that helps; thanks. As you say, there is a loss of the perspective and my concern is that the change in projection could cause overlaps. Can't as I know for sure though.

DREW WILEY
04-30-2013, 02:15 PM
My Sinar 4x5 has 28 inches of bellows, so I'd just grab the thing and be done with it. It would faster than reading thru all the foregoing.

Dan Fromm
04-30-2013, 08:51 PM
My Sinar 4x5 has 28 inches of bellows, so I'd just grab the thing and be done with it. It would faster than reading thru all the foregoing.

Drew, there's no way that either of us, with our antiquated gear, can get the infinite depth of field at any magnification that confocal techniques do. That said, confocal techniques can't be used in the situations where I've shot at high magnification.

Around the turn of the century, one of my collaborators who was also chairman of a college biology department, scraped up $250 k and bought a shiny new confocal microscope. He remarked to me that his professors had better get a lot of good publications with it.

DREW WILEY
05-01-2013, 12:06 PM
What you need Dan is a scanning electron microscope - no good for color, however. I don't think a mere
250K will buy one of those, however ... perhaps a used one.... And confocal techniques per se won't resolve critical diffraction issues. Apochromaticity at high magnifications requires a very specialized kind
of hybrid correction, way out of my $ league. I'd be happy just to have one of those Zeiss research microscopes like I used in college, along with a sheet film holder. They're common, but still in demand
enough to be expensive. The Polaroid holders could be adapted to standard sheet film I think. Or the
Sinar system itself can be adapted to high magnifcation work - you just need a very stable base column
and a lot of rail sections and bellows. I don't really understand all this fuss, however ... unless someone needs 1:1 or some other fixed scale of reproduction, the larger film at smaller aperture will
give better results, and in something printed small like publication, it won't matter anyway. Sometimes
it's fun to look at images on Nikons "Small World" site. Most are false color and taken with expensive
gear from their medical imaging division.