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02-22-2011, 03:42 AM   #391
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Larger than life imagery.
Nice - thanks for sharing Voytech.

02-22-2011, 03:49 AM   #392
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QuoteOriginally posted by yeatzee Quote
Someone try it out and shoot a ruler
Your right.
If you put a 50mm lens on a 50mm tube you get 1:1
You simply divide the lens with the tube ( or the other way around perhaps) so in that case:
50/50=1
The 1 is what you put after of the "1:" so that would make Mag ratio 1:1

Using a 28mm lens on a 50 tube seems to give about 2:1 ( twice life size)

update: Im slightly confused at the moment. I had to give you something shot from a macrolens so here's a ruler shot with a Tokina 90mm f2.5 at f2.5 + a 50mm tube handheld in bad light and I cant wuite get this math working.

90/50=1.8 so that should be mag ratio 1:1.8 ? That doesnt really make sense but it does sort of match the shot.
1.8 inches wide even though the shot looks more like 1.6 inches.

Help!
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Last edited by aliasant; 02-22-2011 at 04:12 AM. Reason: Bad math
02-22-2011, 09:36 AM   #393
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QuoteOriginally posted by mikeSF Quote
here's a new dewdrop shot, this time with the Vivitar 90/2.8 + Raynox 150:
I forgot to mention that I experimented with focus stacking with this image. I shot 6 separate images at f/8 and then very manually combined them in photoshop by layering them all and then creating a mask for the sharpest bits of each layer. It took forever but worked.


BTW, I did download the CombineZM app but could not make heads or tails of how to use it...i better read up on it more. Can it be used to create a stack that can then be edited if it didnt quite get the focus stacking right? In my first try with it I ended up with a composite image that had all sorts of artifacts and did not appear to be able to be tweaked.
02-22-2011, 09:41 AM   #394
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It's a beautiful image Mike.

02-22-2011, 03:44 PM   #395
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QuoteOriginally posted by aliasant Quote
90/50=1.8 so that should be mag ratio 1:1.8 ? That doesnt really make sense but it does sort of match the shot.
1.8 inches wide even though the shot looks more like 1.6 inches.
What about Crop Factor. On our Pentax APS-C cameras, 1:1 is 1.5:1, so shouldn't it be 90/50 = 1.8 x 1.5 = 2.7:1
02-22-2011, 04:37 PM   #396
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QuoteOriginally posted by Damian Quote
What about Crop Factor. On our Pentax APS-C cameras, 1:1 is 1.5:1, so shouldn't it be 90/50 = 1.8 x 1.5 = 2.7:1
The crop factor doesn't change the fact that a macro lens is 1:1, FF or not. The magnification stays the same.
02-23-2011, 03:32 AM   #397
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Cross-posting Sigma105mm Macro



02-23-2011, 05:54 AM   #398
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Cross posting as well, Tammy SP 90mm f2.5 with 01F 2X teleconverter (1:1)


02-24-2011, 08:23 AM   #399
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QuoteOriginally posted by yeatzee Quote
The crop factor doesn't change the fact that a macro lens is 1:1, FF or not. The magnification stays the same.
Where's my brain! Of course you are right.
02-24-2011, 09:43 AM   #400
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QuoteOriginally posted by aliasant Quote
Your right.
If you put a 50mm lens on a 50mm tube you get 1:1
You simply divide the lens with the tube ( or the other way around perhaps) so in that case:
50/50=1
The 1 is what you put after of the "1:" so that would make Mag ratio 1:1

Using a 28mm lens on a 50 tube seems to give about 2:1 ( twice life size)

update: Im slightly confused at the moment. I had to give you something shot from a macrolens so here's a ruler shot with a Tokina 90mm f2.5 at f2.5 + a 50mm tube handheld in bad light and I cant wuite get this math working.

90/50=1.8 so that should be mag ratio 1:1.8 ? That doesnt really make sense but it does sort of match the shot.
1.8 inches wide even though the shot looks more like 1.6 inches.

Help!
your math is about right, I measure horizontally 41mm on the ruler, the pentax frame is about 23.5mm (asp-c) therefore your mag ratio is 1:1.74. the difference could be anything like the position of the focusing collar on the lens, slight errors in actual focal length, and / or whether it is internal or external focus, since internal focused macro lenses work by reducing the focal length (while keeping the front element and working distance constant)
02-24-2011, 07:44 PM   #401
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Wait--this requires math?!
02-25-2011, 02:46 AM   #402
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QuoteOriginally posted by Lowell Goudge Quote
your math is about right, I measure horizontally 41mm on the ruler, the pentax frame is about 23.5mm (asp-c) therefore your mag ratio is 1:1.74. the difference could be anything like the position of the focusing collar on the lens, slight errors in actual focal length, and / or whether it is internal or external focus, since internal focused macro lenses work by reducing the focal length (while keeping the front element and working distance constant)
Ah

I was quite sloppy estimating the ratio
Thanks for the help!

I forgot to mention that I had the Tokina at infinity when I shot that ruler so its real power isnt shown. It should be around 1:1 with the extra 50mm tube.
The tokina extends with zoom, quite a lot as well, so i guess its an external
02-26-2011, 10:03 AM   #403
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Peony Bud

Kinda nightmarish, actually.

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02-26-2011, 07:23 PM   #404
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Tamron 90mm di f 2.8

Dadipentak--that thing looks carnivorous!

Gray Hair Streak

02-27-2011, 10:21 AM   #405
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QuoteOriginally posted by Jewelltrail Quote
Dadipentak--that thing looks carnivorous!
Doesn't it? I just find them fascinating. Here's another shot--this time with the FA 50mm f2.8 macro.

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