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11-10-2011, 11:51 AM   #31
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thanks, when i looked it up, just now, there are 150's and 250's, any advantage to one or the other?

11-10-2011, 11:58 AM   #32
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QuoteOriginally posted by dh4412 Quote
thanks, when i looked it up, just now, there are 150's and 250's, any advantage to one or the other?
The 250 has higher magnification and a nominal working distance of about 5"
The 150's magnification is lower but has a nominal working distance of about 8"
11-10-2011, 12:51 PM   #33
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QuoteOriginally posted by dh4412 Quote
how is the raynox dcr adapter used? does it screw on to the cap threads or ? and what does it do? thanks could it be used on a dfa 100?
Last night I posted this in a related thread:

QuoteOriginally posted by RioRico:
QuoteOriginally posted by Azzy:
Is there any advantage on putting the raynox diopter on a dedicated macro lens (say 100mm pentax / 105 sigma, etc) over 55-300mm ?
That question deserves a test. I mount my +8dpt Raynox DCR-250 on my M42 Vivitar-Komine 90/2.8 macro and extend that fully. Without the Raynox it goes to 1:1. With the Raynox it goes to 2:1. Now I whip out my A-type Tamron 60-300. At 60mm it reaches about 1:1.75 at infinity focus; it vignettes at close focus. At 300mm it reaches about 2.25:1 at infinity focus, and a non-vignetted 3:1 at close focus. My target is a ruler so I can be pretty sure of those numbers.

So the answer is: with a +diopter adapter, you get most magnification with longer lenses at close focus.
newarts provided tons of good info. Another way to see the difference between the DCR-15 and -250 is their +dioptre strength. The -150 is +4.8dpt, the -250 is +8dpt. With this we calculate theoretical magnification: M= F*D/1000, where F is focal length of the host lens and D is dioptre strength of the adapter lens.

Mounting a +8dpt Raynox DCR-250 on a 100mm lens at infinity focus gives M= (100*8)/1000= 0.8:1 or 1:1.25. Using the DCR-150 would give M= (100*4.8)/1000= 0.48:1 or 1:2.1. The -250 thus gives twice the magnification of the -150 on a 100mm lens at infinity focus.

This assumes that 1) the lens is actually 100mm, and 2) that it's at infinity focus. Magnification increases when we extend the lens, as we see in my test above. And if it's an IF (internal focusing) lens, the focal length at infinity won't be the same as at close focus. The difference may be profound. Some have measured the DA18-250 as actually being 200mm at close focus. Focal length changes with IF primes too. Exact magnification thus is flexible; your mileage may vary.

IMHO the best way to determine magnification is to JUST DEW IT! Setup the lens system (host lens, adapter, extension, whatever) and view|snap a metric ruler. Our APS-C sensors are close to 24mm wide and 18mm high (exact size varies) so if we see 4.8cm on the ruler, we know that M= 1:2.

Last edited by RioRico; 11-10-2011 at 01:01 PM.
11-10-2011, 03:33 PM   #34
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Ummm Newarts, there's no way the DoF is the same, much more detail in the 50mm shot... look at the detail on the petal closest to the camera. There's no comparison. That added DoF is what makes the difference in the Bokeh.

11-10-2011, 04:46 PM   #35
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QuoteOriginally posted by normhead Quote
Ummm Newarts, there's no way the DoF is the same, much more detail in the 50mm shot... look at the detail on the petal closest to the camera. There's no comparison. That added DoF is what makes the difference in the Bokeh.
The point of the photo was the difference in background due to the differing lens focal lengths.

I believe the actual DOF (in the sense of focus within the circle of confusion was very close) and I just missed having exactly the same focal plane. The box in the background was many Depths of Field away from the silk flowers.

I'll set up a shot to demonstrate the effect unambiguously & post it soon.
11-17-2011, 08:09 AM   #36
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I bought an FA-100 Macro a couple years ago after buying the K-10. It works at least as well on the K-5, though I do miss the split-screen I installed in the K10. The FA-100 probably isn't as nice as the DFA 100WR, but it performs quite well, IMHO. I don't know whether it's less expensive now... I'm playing with a DA35mm Macro now, but I'm sure I'll use the 100mm for insect pictures, the extra reach makes all the difference.

The rare Bombus affinis in my back yard:
11-17-2011, 11:07 AM   #37
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QuoteOriginally posted by robyn Quote
I've been pondering the same question, but for newborn photography. I've been doing newborn photography for nearly 3 years, but with macro attachments or my 35mm FA limited. I want more. I want the macro. I found this thread when trying to choose between the 100m and 35mm macro, myself.

I need to be close to baby, but I know the 100mm macro can get me closer than a standard 100mm. I've worked with my dad's 100mm macro/Nikor.

So, any have thoughts if it's a baby we're working with- both natural light and lighting?

Thanks- been wrestling with this decision for months, and want to decide in this business year- preferred sooner rather than later-
Sorry Robyn but I don't think you really need a macro lens at all - in fact I know for a fact you don't. Macro is for insects / flowers etc. What are you trying to use a macro lens on a baby for ? Close-ups of it's bogies ?!

Think you need something like a Tamron 17-50 or 28-75.
11-17-2011, 01:16 PM   #38
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QuoteOriginally posted by Frogfish Quote
Sorry Robyn but I don't think you really need a macro lens at all - in fact I know for a fact you don't. Macro is for insects / flowers etc. What are you trying to use a macro lens on a baby for ? Close-ups of it's bogies ?!

Think you need something like a Tamron 17-50 or 28-75.
Or even just the DA18-55, which focuses to 25cm / 10in, plenty close unless one is documenting spiders. I'll admit that I *did* use the Macro-Takumar 50/4 for shooting baby feet, but usually from no closer than 25cm.

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