Newbie question about macro with DSLR

I'm considering buying a Canon Digital Rebel XSi for a project involving
macro photography, and I'm looking for advice regarding macro lenses,
reverse mounts, etc.

Basically I'm trying to photograph a flat subject such that an area
about 1 mm on a side will be full-frame. It would be better yet if
I could do that for an area 0.5 mm on a side.

The camera has an APS-C size sensor (22.2 x 14.8 mm).

I have a precision X-Y stage with stepper motors and microstepping
control, so I can position the subject in increments of less than
0.1 mm. I plan to take many photos with a small shift, and stitch them
together, probably using Hugin. Because I expect there to be a lot of
overlap between the images, I think I can tolerate some amount of
vignetting, spherical abberation, etc.

Is this feasible with some macro lens, combination of lenses, reversing
ring, extension tube, etc?

I'm hoping to avoid the need to buy a microscope and adapter, due to
the cost, though that's obviously an option. I'm not sure how to tell
whether a particular microscope would be suitable without trying it;
for instance, I've looked at a 7x-90x microscope, but apparently 10x
or 20x of that magnification is due to the magnification of the
eyepiece, which I wouldn't have with the camera adapter.

Any advice would be greatly appreciated!

Thanks!
Eric

"Eric Smith" wrote in message
...
I'm considering buying a Canon Digital Rebel XSi for a project involving
macro photography, and I'm looking for advice regarding macro lenses,
reverse mounts, etc.

Basically I'm trying to photograph a flat subject such that an area
about 1 mm on a side will be full-frame. It would be better yet if
I could do that for an area 0.5 mm on a side.

I don't think you will be happy with macro in this instance. Macro is good
for a "magnification" of 1x to 5x and my be able to go to 10x with some
aberation around the edges. At this mag factor the DOF is so tight that the
difference between the distance from the center of the lens to the subject
and the distance from the lens to the side of the subject would be more than
the DOF and so either the center of the image would be in focus or the edge,
not both.

So your need of making .5 to 1 mm full frame would be almost impossible and
so badly formed that you may get only a few clear pixels in the center of
the image. For the level of magnification you are looking for you would be
better off going with a microscope and adapter. Even then you may have
problems with flat focus. You may have to center the subject in the image
and crop the out of focus edges before attempting the stitching.

Good luck

Randy

Randy Berbaum wrote:
"Eric Smith" wrote in message
...
I'm considering buying a Canon Digital Rebel XSi for a project involving
macro photography, and I'm looking for advice regarding macro lenses,
reverse mounts, etc.

Basically I'm trying to photograph a flat subject such that an area
about 1 mm on a side will be full-frame. It would be better yet if
I could do that for an area 0.5 mm on a side.

I don't think you will be happy with macro in this instance. Macro is good
for a "magnification" of 1x to 5x and my be able to go to 10x with some
aberation around the edges. At this mag factor the DOF is so tight that the
difference between the distance from the center of the lens to the subject
and the distance from the lens to the side of the subject would be more than
the DOF and so either the center of the image would be in focus or the edge,
not both.

So your need of making .5 to 1 mm full frame would be almost impossible and
so badly formed that you may get only a few clear pixels in the center of
the image. For the level of magnification you are looking for you would be
better off going with a microscope and adapter. Even then you may have
problems with flat focus. You may have to center the subject in the image
and crop the out of focus edges before attempting the stitching.

This sounds right. A typical macro lens gets to 1:1 and 1mm is 1/18 of
that size (for the height).

On the other hand, how much detail do you need? If cropping, it is pixel
counts that'll tell you what magnification you need. The height (short
side) of a 10MP DSLR is about 2,500 pixels. For a really sharp print,
figure 300 pixels per inch. That will show usable detail for people with
perfect vision but you can easily double that size & still look fine
(150ppi).

Eric Smith wrote

I plan to take many photos with a small shift, and stitch them
together

The bellows arrangements which allow this kind of shifting the camera
with the lens held in place aren't cheap, or at least not common for
35mm work.

Eric Smith wrote:
I'm considering buying a Canon Digital Rebel XSi for a project involving
macro photography, and I'm looking for advice regarding macro lenses,
reverse mounts, etc.

Basically I'm trying to photograph a flat subject such that an area
about 1 mm on a side will be full-frame. It would be better yet if
I could do that for an area 0.5 mm on a side.

The camera has an APS-C size sensor (22.2 x 14.8 mm).

I have a precision X-Y stage with stepper motors and microstepping
control, so I can position the subject in increments of less than
0.1 mm. I plan to take many photos with a small shift, and stitch them
together, probably using Hugin. Because I expect there to be a lot of
overlap between the images, I think I can tolerate some amount of
vignetting, spherical abberation, etc.

Is this feasible with some macro lens, combination of lenses, reversing
ring, extension tube, etc?

I'm hoping to avoid the need to buy a microscope and adapter, due to
the cost, though that's obviously an option. I'm not sure how to tell
whether a particular microscope would be suitable without trying it;
for instance, I've looked at a 7x-90x microscope, but apparently 10x
or 20x of that magnification is due to the magnification of the
eyepiece, which I wouldn't have with the camera adapter.

Any advice would be greatly appreciated!

Thanks!
Eric

I don't know what your ultimate goal might be....BUT....
The following option may work for you and it is very inexpensive.
See: http://www.jr.com/JRProductPage.process?Product=4220456
Bob Williams

"BobW" writes:
I found that Canon document and it looks like the best magnification you can
get *is* with their MP-E65mm f/2.8 1-5x macro lens (5x max magnification).
With a 25mm extension tube, the best you can get is about 1.25x with a
non-macro lens (the 24-70mm f/2.8L), or 1.39x with their EF 100mm f/2.8
macro USM lens.

So the extension tube gets me less magnification? I thought the point
of it was to get more?

I'm looking at Canon's chart:
http://consumer.usa.canon.com/app/pd...FLensChart.pdf

The list the EF 180mm f/3.5L Macro USM as having a magnification of 10.9x
when used with the EF 12 II extension tube. Is this a typo?

How does the magnification achievable with reverse-mounting a lens
compare with that of macro lenses?

Paul Furman wrote:
Eric Smith wrote

I plan to take many photos with a small shift, and stitch them
together

The bellows arrangements which allow this kind of shifting the camera
with the lens held in place aren't cheap, or at least not common for
35mm work.

Didn't he describe owning a very nice platform to shift
the position of the object, not the camera. It should
do fine.

--
Floyd L. Davidson http://www.apaflo.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)

Randy Berbaum wrote:
"Eric Smith" wrote in message
...
I'm considering buying a Canon Digital Rebel XSi for a project involving
macro photography, and I'm looking for advice regarding macro lenses,
reverse mounts, etc.

Basically I'm trying to photograph a flat subject such that an area
about 1 mm on a side will be full-frame. It would be better yet if
I could do that for an area 0.5 mm on a side.

I don't think you will be happy with macro in this instance. Macro is good
for a "magnification" of 1x to 5x and my be able to go to 10x with some
aberation around the edges. At this mag factor the DOF is so tight that the
difference between the distance from the center of the lens to the subject
and the distance from the lens to the side of the subject would be more than
the DOF and so either the center of the image would be in focus or the edge,
not both.

So your need of making .5 to 1 mm full frame would be almost impossible and
so badly formed that you may get only a few clear pixels in the center of
the image. For the level of magnification you are looking for you would be
better off going with a microscope and adapter. Even then you may have
problems with flat focus.


The OP needs a microscope objective. With a good one flat field is
no problem. He needs a 20 or 40x one for best results. I am assuming
a truly flat subject where no depth of field is needed. It DOF
is needed, then the only hope is "slices" added up in software.

Remember that at 20x magnification, at f/1 AT THE SUBJECT
you get f/20 AT THE SENSOR. F/1 or even f/0.8 is available
in microscope objectives he can use. F/0.35 is available but
useless for his application (works only in oil!). Those are at the subject.

This is a specialized application. HE does NOT want an microscope since
he already has the stepper motor setup, he just need the objective
and some sort of illumination system. Olympus makes, or at least used to make,
the best equipment for this.

NOTE: some newer objectives are not designed to focus down on the
output side and need a "tube lens". These may have inacceptable
lateral chromatic if used without the manufacturer's tube lens.


Doug McDonald

In article , Eric Smith says...
I'm considering buying a Canon Digital Rebel XSi for a project involving
macro photography, and I'm looking for advice regarding macro lenses,
reverse mounts, etc.

Basically I'm trying to photograph a flat subject such that an area
about 1 mm on a side will be full-frame. It would be better yet if
I could do that for an area 0.5 mm on a side.

The camera has an APS-C size sensor (22.2 x 14.8 mm).

Have you considered a camera with a small sensor? Would be better
capable of photographing very small objects.
--

Alfred Molon
------------------------------
Olympus 50X0, 8080, E3X0, E4X0, E5X0 and E3 forum at
http://tech.groups.yahoo.com/group/MyOlympus/
http://myolympus.org/ photo sharing site

Alfred Molon wrote in
:

In article , Eric Smith
says...
I'm considering buying a Canon Digital Rebel XSi for a project
involving macro photography, and I'm looking for advice regarding
macro lenses, reverse mounts, etc.

Basically I'm trying to photograph a flat subject such that an area
about 1 mm on a side will be full-frame. It would be better yet if
I could do that for an area 0.5 mm on a side.

The camera has an APS-C size sensor (22.2 x 14.8 mm).

Have you considered a camera with a small sensor? Would be better
capable of photographing very small objects.


You’re going to need to use a microscope to get that much magnification.
I use a 20mm bellows mount macro lens and bellows with my digital rebel
and I can’t get that much magnification. No extension tube, reverse
mount will do what you want. Your best bet is to get a microscope and
mount adapter so the camera can be used on it. Note: the bellow mount
macro and bellows are old Cannon equipment made for the FD series film
camera. You can get it on E-Bay now and then but it will cost you an arm
and leg for it. Basic information:
The magnification you get is set by the number of focal lengths the lens
is from the film/senor. A 50mm lens 50mm from the film/sensor is a
magnification of 1 A 20mm lens, 200mm from the film/sensor has a
magnification of 10. In macro photography magnification is measure by
the size of the image on the film/sensor. So with a magnification of 1,
if the object is 1mm tall, it will be 1mm tall on the film/senor. Given
that you will need a magnification of 14 to fill you sensor. For my 20mm
macro lens it would need to be 280mm away from the sensor, far longer
than any bellows I know about. Note: reversing the lens doesn’t change
its focal length, just its optical performance close up (makes it
better). A smaller senor sounds like it would help, but in real life
given the longer expose need for macro work, the increased noise from
the small sensor offsets any advantage you might get. Hope this helps

John Passaneau