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05-16-2010, 08:08 PM   #31
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Hey, yeatzee !

Is that You in the attached youtube video?
Is the spider picture you've attached taken by you during that video ?!

05-16-2010, 08:22 PM   #32
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The Canon MP-E 65 and MT-24EX system (and I've had the pleasure of trying one out) is really designed to be a "field' system. In other words, mobile and outdoors. It's extremely difficult to take a shot at 5x handheld without more practise time than I got.

Unless you're chasing a moving target, the almost scientific/microscope design of the Canon system is overkill for many macro situations. It's very costly and you need extreme patience and solid hand/eye coordination.

For studio work or stationery tripod use, less dedicated or expensive systems can be utilized, some with apparently better quality than the Canon set-up (keeping in mind the Canon rig is very mobile by design):

Canon MP-E 65

No Cropping Zone: "The Bee Man"

Gear - a set on Flickr

It sound like you'll be doing stationary work. For that, a bellows with an enlarging lens will be extremely sharp and detailed. Enlarging lenses from Nikon and Fuji are absolutely razor crisp and Nikkors are readily available on eBay.

Are you sure you need 5x? That's some extremely shallow DOF. 3-4x will get you most of the way there.

For lighting there are a few options for achieving what you want. The "bee man" above lays out a good case, as does Strobist in a number of blog entires. With the CF arms you already have, you're already mostly there.

You may also need to consider focus stacking software. There is a company called Helicon that is trying to merge the Canon/Nikon tether to control multiple focal length shots for auto-combining. That's the future for the DOF issue.


QuoteOriginally posted by mrpink Quote
Yes, I would grab a set of MT-24EX, if i decide to go for the mp-e.

If I stay with the K20D for macro-work (and I'd like to stay with it), is there a limitation to how long an extension (how many extension tubes on top of each other) can one use to achieve desired magnification? Basically I'll be looking at 175mms worth of extensions (if I use a 35mm 1:1 macro lens) to achieve 5:1 magn. Does anyone of you fine people have anything against doing this setup? I'd be using a focusing rail under the camera on the tripod, and either MT-24EX dual flashes, or a single ring-flash. (I also have custom carbon-fiber arms that attach to the tripod and hold a flash near the end of the glass).
05-16-2010, 08:23 PM   #33
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QuoteOriginally posted by mrpink Quote
Is that You in the attached youtube video?
Is the spider picture you've attached taken by you during that video ?!
Yes that is me.

No I took the shot, got questions on my setup, and made the video.
05-17-2010, 07:19 AM   #34
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Sensor_lens_distance=Focal_length(1+Magnification)

So for a magnification of 5 you need 6 focal lengths from the lens to the sensor.

Subject_lens_distance=Focal_length(1+1/Magnification)

So for a magnification of 5 the subject will be 1.16 Focal lengths from the lens.

Say you use a 30mm lens and a bellows for a magnification of 5:

The bellows must be extended so the lens-sensor distance is 180mm (since the camera mount to sensor distance is about 45mm, the actual bellows extension will be 135mm.)

At this magnification the subject will be about 30(1.16)=32.8mm from the subject. The lens is one focal length from the subject for infinite magnification.

If you use a longer lens, both bellows and working distances will be larger.

The numbers are based on thin lens theory and are approximate for a complex lens.

It doesn't matter if you reverse the lens or not - the main effect of lens reversal is simply to move the lens a little further from the sensor.

You should be able to buy a used bellows for less than $50. Here's one for $42 delivered:
Macro Fold Bellows for PENTAX K-m K20D K10D K200D K100D - eBay (item 230471079193 end time Jun-04-10 21:09:46 PDT)

At 5X you might be best off getting a proper microscope...Basically a microscope is set up to move the tiny subject, not the clunky device.


Last edited by newarts; 05-17-2010 at 11:00 AM. Reason: corrected math error
05-17-2010, 07:33 AM   #35
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I am surprised no one has mentioned the true macro lenses yet. In fact, lenses that go up to 1:1 magnification ratio are close focus lenses rather than true macro lenses, but there are also many lenses that were especially designed to shoot at 2:1 to 6:1 ratio (2x to 6x life size), or even more. Most of the time, these lenses are in RMS mount (a smaller screw mount mainly used for microscope objectives) but adapters are available to mount them on M42 or PK bellows. They have an aperture ring but not focusing helicoid. The most famous ones are the Zeiss Luminar, Leitz Photar, Macro Nikkor, Zuiko Macro or Canon Macro Photo Lenses. I have the Canon Macro Photo 35mm F/2.8, which is a very sharp lens with a magnification range of 1.8:1 to 5:1 and a relatively fast aperture of F/2.8 -- at least for a true macro. Here's a picture of this lens:


Picture Credit: The Macrolens Collection Database ęKlaus D. Schmitt - All rights reserved

You'll find a fairly complete list of these lenses of the impressive website of Dr. Klaus D. Schmitt, and also more info about Macro Nikkor lenses on Bj°rn R°rslett's website.

Cheers!

Abbazz
05-17-2010, 09:03 AM   #36
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Abbazz, I have one of those Canon bellows macro lenses. The reason I don't mention them in these beginning type threads it that they are highly specialized and expensive.
05-17-2010, 09:05 AM   #37
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QuoteOriginally posted by newarts Quote
. . .
At 5X you might be best off getting a proper microscope...Basically a microscope is set up to move the tiny subject, not the clunky device.
Actually, 5-10x is more in the realm of a stereoscope (aka dissecting scope) which usually have stationary stages.
05-17-2010, 10:37 AM   #38
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Take a look at this:
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/86633-%5Bmacro...55mm-28mm.html

Just another way of doing it.

05-17-2010, 11:11 AM   #39
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about 10:1 with extension tube K100, about 10cm extra extension with the auto bellows, and then a reversed 28mm.

When using a reversed 50mm, you get this (about 5:1) :
05-17-2010, 01:32 PM   #40
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QuoteOriginally posted by glasbak Quote
ension tube K100, about 10cm extra extension with the auto bellows, and then a reversed 28mm.
Nice. I have that set-up. What's your light source?
05-17-2010, 02:29 PM   #41
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QuoteOriginally posted by Aristophanes Quote
Nice. I have that set-up. What's your light source?
Thanks, the first picture I used an af080c ring flash, the second a af360fgz.
05-17-2010, 05:04 PM   #42
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QuoteOriginally posted by mrpink Quote
I'd like to fill my 24" screen with a bug's eye though.
A bug's eye?


(Click to enlarge)
Alien Bee Eye



This is a bee's left eye, rotated 90░ and in 6:1 magnification. If you click it and select original (O) size you'll get a 1920pixel version which already shows the green wavelength light interference lines at the intersection of the eye segments. Detail of about 1.5Ám or maybe better is resolved! (refer to the attachment)

Taken with a Zeiss 50/1.4 at f/4.0. Without bellows because they don't provide the best possible image quality except if used with a macro lens like the DA35.

I mounted the Zeiss 50 filter ring to the filter ring of a DA*300/4 and this provides stunning image detail. The magnification then is 300:50 or 6:1.

The crucial part is the Zeiss as it must resolve the detail. It's ability to resolve 1.5Ám means it resolves 330 lp/mm in the center or better. Something not normally measurable with a digital camera

Mounting a good prime to a zoom provides adjustable magnification. Note that both lenses are set at infinity focus and actual focussing is done by adjusting the subject distance which always is the flange distance (45mm).

Last edited by falconeye; 06-15-2011 at 05:29 AM.
05-17-2010, 05:25 PM   #43
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Thanks falconeye !

So zoom lens to the body and then reversed 50mm Zeiss to the zoom lens?

What can be done about that DOF (if money is no subject) you think ?

Thanks.
05-17-2010, 05:28 PM   #44
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Its a prime 300mm lens, not a zoom he is refering to. The only way to get more DOF without softening from diffraction is focus stacking...... period.
05-17-2010, 05:51 PM   #45
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QuoteOriginally posted by yeatzee Quote
Its a prime 300mm lens, not a zoom he is refering to.
Yes, the long lens to the body. This is why EXIF shows 300mm and infinity distance
The short lens must be a lens with a resolution outresolving the sensor by a large factor! So, very good is not necessarily good enough. Search for a prime lens which is sharper at f/4 than at f/5.6.
QuoteOriginally posted by yeatzee Quote
The only way to get more DOF without softening from diffraction is focus stacking...... period.
That's the point. 5:1 with 5Ám pixels means 1Ám detail and we're operating at the limits of optics.

"Photons may be larger than they appear" is written in capital letters in your images if you magnify this much

I used f/4 which has little DoF. But this is the lens' best resolving aperture. Close the aperture and diffraction kills effective magnification. Microscopes are f/1 for a reason...

Focus stacking is key and you'll need many photos.

You may find it hard to find a DoF calculator which covers this situation.

You get 5Ám blur at f/4 at 20Ám from the focus plane and this is your DoF!

So, to cover a 4mm bee head requires 4000Ám/40Ám or 100 photos!


And one last word:

Light is like from a f/4:6 (f/24) aperture and shake is like from a 300mmx6 (1200mm) lens.

So, this is like taking 100 1200mm f/24 photos. Have a good macro rail and a very good lighting solution. It's all shaky and dark like hell ...

If you want to mount a ring flash, you'll need a K-mount filter ring adapter which doesn't exist. Building one yourself from a spare rear lens cap is the nly solution I am aware of. It is easier than it sounds by using filter size step adapter rings.

Last edited by falconeye; 05-17-2010 at 05:56 PM.
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