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Is it possible to get 20-40:1 macro @ home?
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PostPosted: Sun Feb 23, 2014 6:28 pm    Post subject: Reply with quote
CuriousOne wrote:
WOW, impressive!

But what you mean by "stack" ?

stack photos due to bad illumination to increase the brightness, as astronomy guys do?


By "stack" I mean "focus stack". Basically you take a sequence of shots at different focal planes, with step size between planes somewhat smaller than half the depth of field. Software is then used to identify the pixels that are in focus from each focal plane, and to make a composite image using only the in-focus pixels.


PostPosted: Sun Feb 23, 2014 6:59 pm    Post subject: Reply with quote
AMDBill wrote:
hello

could you post a photo of your set-up for macro fungus shooting ? please


The setup is similar to many that are pictured over on photomacrography.net. Mine consists of:

Canon T2i
Canon Bellows
Microscope objective
Stepper focusing rail


PostPosted: Sun Feb 23, 2014 7:42 pm    Post subject: Reply with quote
I've forwarded these pics to a student which studies at microbiology course. As he says, from his level of knowledge, these tree root like structures does not look like fungus, more likely of some kind of crystalization. But he's not sure, so he'll ask tomorrow his teacher.


PostPosted: Mon Feb 24, 2014 4:25 am    Post subject: Reply with quote
CuriousOne wrote:
I've forwarded these pics to a student which studies at microbiology course. As he says, from his level of knowledge, these tree root like structures does not look like fungus, more likely of some kind of crystalization. But he's not sure, so he'll ask tomorrow his teacher.


The "fractal" looking colony is pretty normal looking. I've seen that type both on lens surfaces as well as between layers. I have no idea the classification but am pretty sure it is a fungus and not a crystal formation.


PostPosted: Mon Feb 24, 2014 7:04 am    Post subject: Reply with quote
Fungus it is for sure.


PostPosted: Wed Feb 26, 2014 3:00 pm    Post subject: Reply with quote
CuriousOne wrote:
I've forwarded these pics to a student which studies at microbiology course. As he says, from his level of knowledge, these tree root like structures does not look like fungus, more likely of some kind of crystalization. But he's not sure, so he'll ask tomorrow his teacher.


What was the outcome of the inquiry?


PostPosted: Fri Feb 28, 2014 1:28 am    Post subject: Reply with quote

Mushroom in a lens von Chloressigsäureethylester auf Flickr

Here a similar fumgus at lower magnification

The pseudocrystalline tree structure is normal for mycelia which grow on glas


PostPosted: Sat Mar 01, 2014 6:42 am    Post subject: Reply with quote
Yes, teacher said such fungus do exist, but not common in our area, he told the name but I've forgotten.

I have another question.

I have adapted vivitar 70-210/4.5 1:1 macro to Sony A57. I'm using Petri 55/2 reverse mounted in front of vivitar as close-up lens. Currently, the test sample sized 5.4x3.2mm, occupies 4461x2634 pixels of the APS-C frame. If converted to milimeters @ 300dpi, this is 377x223mm. So what is the magnification?

I also have microscope calibration glass, with lines at each 0.01mm. When photographed, spacing between these lines is 6 pixels.


PostPosted: Sat Mar 01, 2014 1:35 pm    Post subject: Reply with quote
CuriousOne wrote:
Yes, teacher said such fungus do exist, but not common in our area, he told the name but I've forgotten.

I have another question.

I have adapted vivitar 70-210/4.5 1:1 macro to Sony A57. I'm using Petri 55/2 reverse mounted in front of vivitar as close-up lens. Currently, the test sample sized 5.4x3.2mm, occupies 4461x2634 pixels of the APS-C frame. If converted to milimeters @ 300dpi, this is 377x223mm. So what is the magnification?

I also have microscope calibration glass, with lines at each 0.01mm. When photographed, spacing between these lines is 6 pixels.


Your A57 sensor is 23.5mmx15.6mm, and has 4912x3264 pixels. This makes the pixel pitch 4.78um.

The size of the image on your sensor is 4.78um *4461 x 4.78um*2634 = 21.3mm x 12.6mm

Your magnification is 21.3/5.4 = 3.94. As a check, also calculate 12.6/3.2 = 3.94. So your magnification is 3.94:1.

Ray


PostPosted: Sat Mar 01, 2014 3:17 pm    Post subject: Reply with quote
Thanks!

I also have binocular microscope, with variable magnification range, and image similar I see in viewfinder of my camera (coverage of visible area by sample), is around 20x magnification. Are these different "X" -es or?


PostPosted: Sat Mar 01, 2014 3:19 pm    Post subject: Reply with quote
And another question, if you don't mind.

My vivitar lens says that it can do 1:1 macro. By adding 50mm lens reverse in front of it, I got about 4:1 macro. So how reverse mounted lens MM impacts magnification ratio? I should try say 28mm, to get higher magnification, or should try 100mm?


PostPosted: Sat Mar 01, 2014 4:00 pm    Post subject: Reply with quote
CuriousOne wrote:
Thanks!

I also have binocular microscope, with variable magnification range, and image similar I see in viewfinder of my camera (coverage of visible area by sample), is around 20x magnification. Are these different "X" -es or?


They are different. The 20x is the magnification including the eyepieces on your microscope. If your eyepieces are 10x, then the microscope body is working at around 2x.


PostPosted: Sat Mar 01, 2014 4:08 pm    Post subject: Reply with quote
CuriousOne wrote:
And another question, if you don't mind.

My vivitar lens says that it can do 1:1 macro. By adding 50mm lens reverse in front of it, I got about 4:1 macro. So how reverse mounted lens MM impacts magnification ratio? I should try say 28mm, to get higher magnification, or should try 100mm?


Are you absolutely sure your 70-210 Vivitar says it can do 1:1? I've never heard of such a lens. If so, would you please post a picture of it? Most 70-210 (a popular range long ago, many mfrs made one) will go to perhaps 1:4 max. Even the Nikon 70-180 Micro-Nikkor only goes to 1:1.3 natively.

For best results in a "stacked lens" arrangement like you're using, you should focus the "tube lens" (your 70-210) at infinity, and also focus your "objective lens" (50mm) at infinity for best results. Open the aperture of the tube lens all the way up, or perhaps one stop down max.

The ratings for magnification on the tube lens and objective lens are completely irrelevant to your final magnification. All that matters is the ratio of focal lengths, assuming you have both lenses focused at infinity for best results. You can calculate the magnification simply with following formula:

M = FL(tube) / FL (objective)

If you have the tube lens set at 210, then your magnification is:

M = 210 / 50 = 4.2:1

Set the tube lens at 70mm and you get M = 1.4:1, but you will likely see vignetting.


PostPosted: Sat Mar 01, 2014 4:10 pm    Post subject: Reply with quote
CuriousOne wrote:
And another question, if you don't mind.

My vivitar lens says that it can do 1:1 macro. By adding 50mm lens reverse in front of it, I got about 4:1 macro. So how reverse mounted lens MM impacts magnification ratio? I should try say 28mm, to get higher magnification, or should try 100mm?


The magic formula is: magnification = (focal length of "prime" lens)/(focal length of "supplementary" lens)

The "prime" lens is attached to the camera body, focus set to infinity. The "supplementary lens" is reversed, attached to the front of the "prime" lens, focus set to infinity.


PostPosted: Sat Mar 01, 2014 4:13 pm    Post subject: Reply with quote
My microscope has x9 eyepieces and adjustable magnification, 0.6X to 7X.


PostPosted: Sat Mar 01, 2014 5:02 pm    Post subject: Reply with quote
Here is the close-up of lens focusing ring, clearly showing 1:1 macro option position:



The lens itself not rare, widely available and I like it very much, but it has one strange point - pin sharp focusing ring, even at 200 meter, you need VERY PRECISE adjustment of focus, to get things in focus.


PostPosted: Sat Mar 01, 2014 5:07 pm    Post subject: Reply with quote
Ahh, I hate to tell you but that doesn't say "1:1", it says "1.1" and is on the "METER" scale. It means you can focus as close as 1.1 Meters from your subject. This will probably be around 1:4 magnification...Ray


PostPosted: Sat Mar 01, 2014 5:25 pm    Post subject: Reply with quote
Whatsoever, it works just fine Smile and calculations above show it works in the 1:1 way Smile


PostPosted: Sat Mar 01, 2014 5:45 pm    Post subject: Reply with quote
And how high I can go?

For example, I have 400/6.3 lens and 17/2.8 one. this should yeld me 400/17=23:1 magnification?


PostPosted: Sat Mar 01, 2014 5:48 pm    Post subject: Reply with quote
CuriousOne wrote:
And how high I can go?

For example, I have 400/6.3 lens and 17/2.8 one. this should yeld me 400/17=23:1 magnification?


It will.


PostPosted: Sat Mar 01, 2014 5:49 pm    Post subject: Reply with quote
WOW!

I need 67mm coupling ring them (both have 67mm tread)


PostPosted: Sat Mar 01, 2014 6:06 pm    Post subject: Reply with quote
CuriousOne wrote:
WOW!

I need 67mm coupling ring them (both have 67mm tread)


http://www.ebay.com/itm/67-67mm-Close-Up-Macro-Coupler-Reverse-Reversing-Metal-Ring-Adapter-67mm-to-67mm-/370592917627?pt=US_Lens_Adapters_Mounts_Tubes&hash=item56490f287b


PostPosted: Sat Mar 01, 2014 6:27 pm    Post subject: Reply with quote
I'll machine one for myself on monday, have lathe @ office.

But, I've just tried 400mm+50mm reverse. Not impressive, only slightly larger than 210+50mm. Added some macro rings and it helped a bit, now image exceeds camera sensor size, but very hard to focus Sad


PostPosted: Sat Mar 01, 2014 9:32 pm    Post subject: Reply with quote
CuriousOne wrote:
I'll machine one for myself on monday, have lathe @ office.

But, I've just tried 400mm+50mm reverse. Not impressive, only slightly larger than 210+50mm. Added some macro rings and it helped a bit, now image exceeds camera sensor size, but very hard to focus Sad


If the 400mm is not almost twice the size of the 210, then something is amiss. Did you have both focused at infinity for both configurations?

It will of course be hard to focus due to very narrow depth of field. Will require a stand with focus capability on order of a few microns...


PostPosted: Sun Mar 02, 2014 4:30 am    Post subject: Reply with quote
Yes, it is large and long Tele-Astranar 400mm/F6.3 and both lens were focused on infinity.

For the focusing table, I think it is possible to build a stepper motor driven one, for precise focusing.
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