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05-17-2010, 05:51 PM   #46
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QuoteOriginally posted by Peter:
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. ....
I don't follow this. Why would the zeiss perform worse with no intervening lens than with an intervening lens (the 300:50 arrangement)? How could the resolution of the 50mm Zeiss be improved by even a perfect 300mm lens?

05-17-2010, 06:10 PM   #47
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QuoteOriginally posted by newarts Quote
I don't follow this. Why would the zeiss perform worse with no intervening lens than with an intervening lens (the 300:50 arrangement)? How could the resolution of the 50mm Zeiss be improved by even a perfect 300mm lens?
The Zeiss focusses at infinity. This is its sweet spot. Macro lenses are designed for short subject distances, normal primes aren't.

A reverse mounted 50 is forced to operate close at its near focus distance. At 6:1, the bellows would have to be 7f or 350mm which is still less than the 460mm near distance limit of a (Zeiss) 50.

Not only the lens woudn't be used at a non optimal setting, it would be used outside of its specification. And this where we require it to outresolve a sensor by 6x! I wouldn't expect usable results.

(When pixel peeping but this is what counts as otherwise, I can use the DA35 and crop. The DA35 is an exceptional lens and cropping a DA35 may beat a bellows approach -- what most people forget: a 5:1 macro resized for the web (900px) only is a 1:1 macro...

So, to the OP ... Wanting a 5:1 macro for a 24" screen (1920px wide) means wanting a (tac-sharp) 2:1 macro really)

Last edited by falconeye; 05-17-2010 at 06:16 PM.
05-17-2010, 06:31 PM   #48
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QuoteOriginally posted by falconeye Quote
Yes, the long lens to the body. This is why EXIF shows 300mm and infinity distance

That's the point. 5:1 with 5Ám pixels means 1Ám detail and we're operating at the limits of optics.
Right, which is why I said it :ugh:
05-17-2010, 07:52 PM   #49
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It isn't so hard or expensive to get 10:1

I reversed a 24mm lens on a Vivitar 2X macro teleconverter and was able to achieve 10:1 ! It was a pretty inexpensive and compact setup. Look at the following two posts for some photos and a picture of the setup.

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/43370-ultra-cl...tml#post411705

05-17-2010, 08:19 PM   #50
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Thanks, Pentaxman

for the most interesting setup suggestion thus far.

Now only if we could figure out a way to change magnification on he fly...
This setup will give us a fixed 10:1, correct ?
05-17-2010, 08:31 PM   #51
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QuoteOriginally posted by pentaxman Quote
I reversed a 24mm lens on a Vivitar 2X macro teleconverter and was able to achieve 10:1 ! It was a pretty inexpensive and compact setup. Look at the following two posts for some photos and a picture of the setup.

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/43370-ultra-cl...tml#post411705
Im not quite convinced a 2x TC being used for extreme mag. will hold up IQ wise... prove me wrong
05-17-2010, 09:19 PM   #52
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QuoteOriginally posted by yeatzee Quote
Im not quite convinced a 2x TC being used for extreme mag. will hold up IQ wise... prove me wrong
Look at the detail in the picture I took of the metal ruler. Remember - the markings are 1mm apart. You can see every little scratch and imperfection in the surface of the ruler. If this does not convince you, take out a $1 bill and look at the size of the eye on top of the pyramid, then look at the picture in the post. I know that this is subjective proof, but it is hard to get test targets optimized for 10:1 reproduction.
05-17-2010, 09:46 PM   #53
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I understand the great mag. these are taken about. Im not talking about that, but rather IQ.

05-17-2010, 10:16 PM   #54
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QuoteOriginally posted by yeatzee Quote
I understand the great mag. these are taken about. Im not talking about that, but rather IQ.
I am talking IQ also. If you are talking color, contrast and resolution, I took pictures both with and without the converter and could not tell any obvious differences in IQ. If there was a loss in IQ due to the converter, it was minimal.
05-18-2010, 03:34 AM   #55
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QuoteOriginally posted by pentaxman Quote
Look at the detail in the picture I took of the metal ruler. Remember - the markings are 1mm apart.
I agree, the images from this setup have good IQ at the resolution shown (1024).

As I mentioned above though, this is 2:1 magnification after resizing them for the web. I can see more detail in my 6:1s at the 100% level. But IQ starts to decrease then. I would say my setup holds good IQ up to about 4:1. Can you please provide a 100% crop from your setup so we estimate IQ for your's as well? What is the absolute size of details (Ám) you're still resolving (the pixels in your web image are 2.5mm/1024 or 2.5Ám -- if you approach 1Ám, things start to get tricky ...).
05-18-2010, 05:24 AM   #56
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Fascinating thread!

To the OP: The Canon MP-E65 is basically a reversed mounted 35mm. No magic; you can get that cheaper yourself.

I think a short lens reverse mounted to a long zoom is your best bet. But please use a male-to-male reverse adapter and no tape. If you do use tape don't tell us and please don't post images of the setup. Images of lenses taped together where you invariably see a slight kink in the connection make me sick. I mean it.
05-18-2010, 06:50 AM   #57
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Those are not crops - they are full frame resized. They are actually 10:1.

Tom


QuoteOriginally posted by falconeye Quote
I agree, the images from this setup have good IQ at the resolution shown (1024).

As I mentioned above though, this is 2:1 magnification after resizing them for the web. I can see more detail in my 6:1s at the 100% level. But IQ starts to decrease then. I would say my setup holds good IQ up to about 4:1. Can you please provide a 100% crop from your setup so we estimate IQ for your's as well? What is the absolute size of details (Ám) you're still resolving (the pixels in your web image are 2.5mm/1024 or 2.5Ám -- if you approach 1Ám, things start to get tricky ...).
05-18-2010, 07:34 AM   #58
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QuoteOriginally posted by mrpink Quote
Maybe I outta get a Canon body just to accommodate the mp-e65 lens.
This in no way changes the basic physics of the matter: if you want 5:1 magnification with a short focal length, you need incredibly short working distances. Macro photography doesn't work by magic. it works by two things and two things only: the longer the focal length, the larger an object appears from the same distance (just as is the case in "regular" photography), and the closer you get to a subject, the bigger it looks (just as is the the case in "regular" photography - or when looking at a subject without a camera. there is nothing special a "macro" lens does above and beyond this to achieve more magnification. It's a simple function of focal length and working distance, period. The shorter the focal length, the shorter the working distance required to get a given amount of magnification. Doesn't matter if you do this by using extension tubes, stacking lenses, reversing them, or buying super expensive lenses that do one or more of these thing internally for about 100 times the cost of doing it yourself.
05-18-2010, 08:06 AM   #59
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QuoteOriginally posted by Marc Sabatella Quote
This in no way changes the basic physics of the matter: if you want 5:1 magnification with a short focal length, you need incredibly short working distances.
Sorry, not true, when using a retrofocus wideangle lens reverse mounted, you always have a relative generous working distance.
It is the same distance that is required for the reflex mirror box.
05-18-2010, 09:30 AM   #60
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As you can see from this link, the working distance is not too bad. This is a 24mm reversed with a 2X macroconverter.

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/43370-ultra-cl...tml#post411715


QuoteOriginally posted by glasbak Quote
Sorry, not true, when using a retrofocus wideangle lens reverse mounted, you always have a relative generous working distance.
It is the same distance that is required for the reflex mirror box.
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