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Old Jan 31, 2012, 5:13 AM   #11
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Hi Ashley, hope you don't mind me popping this shot into here (it's not going to stand up anywhere on it's own) as I thought it might be interesting !

Before I buy a telescope / scope, for digiscoping, I wanted to again try the Tamron 500 with the Pentax AFA x1.7 (equals 850mm) to see how good an image I could get out of the combination. Here is the best of 4 (hand-held, wedged against the window frame) :

Tamron 500 + AFAx1.7 = 850mm @ ISO800 - f13.6 - 1/180 (NR and sharpening applied in PP). Please remember that the screen grab (using Skitch) and this forum's software will both have impacted the actual sharpness as viewed in Aperture / as shot, to some degree. On the left is the shot after minor cropping and on the right the 100% crop. What do you guys think of the IQ produced ?

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Pentax : 15 Ltd, 77 Ltd, 43/1.9 Ltd, Cosina 55/1.2, DA*300/4, Contax Zeiss Distagon 28/2.8, Raynox 150/250, AFA x1.7, Metz 50 af1.

Nikon : D800, D600, Sigma 500/4.5, Sigma 120-300/2.8, Zeiss Distagon ZF2 - 21/2.8, Zeiss Distagon ZF2 - 35/2.0, Nikkor 85/1.8G, Sigma 50/1.4. Nikon x1.4 TC, Sigma x2.0 TC

Last edited by Frogfish; Jan 31, 2012 at 5:17 AM.
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Old Feb 1, 2012, 3:14 PM   #12
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I don't mind you putting that here, and actually gives me the perfect opportunity to ask about crop factors.

As it's a 35mm lens, wouldn't that make it 750mm natvely, so with the 1.7TC it would be 1275mm in total?

I must admit to being confused about the cropped equivalent when it comes to stuff like this, and for shake reduction, should I enter the lenses true value (500mm) or the cropped 750mm?

Cheers
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Pentax K-7
Tamron 90mm SP Di Macro
Tamron Adaptall 2 - 28mm, 28-80mm, 500mm Mirror
Pentax KAF - 18-55mm WR, 28-105mm PowerZoom
Pentax K - 50mm f/2, 50mm f/1.7, 28mm f/2.2
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Old Feb 1, 2012, 8:41 PM   #13
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Quote:
Originally Posted by Tachikoma View Post
I don't mind you putting that here, and actually gives me the perfect opportunity to ask about crop factors.

As it's a 35mm lens, wouldn't that make it 750mm natvely, so with the 1.7TC it would be 1275mm in total?

I must admit to being confused about the cropped equivalent when it comes to stuff like this, and for shake reduction, should I enter the lenses true value (500mm) or the cropped 750mm?

Cheers
It would make it the equivalent of 1,275mm on a 35mm but in actuality there is no difference because of the extra size of a 35mm sensor (and size & quality of pixels), by the time you crop the shot to the APS-C size you will have the same equivalent FL and IQ.

On your crop camera (all digital Pentaxes) you input the actual FL of the lens for SR and NOT it's equivalent FL on a cropped sensor.
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Pentax : 15 Ltd, 77 Ltd, 43/1.9 Ltd, Cosina 55/1.2, DA*300/4, Contax Zeiss Distagon 28/2.8, Raynox 150/250, AFA x1.7, Metz 50 af1.

Nikon : D800, D600, Sigma 500/4.5, Sigma 120-300/2.8, Zeiss Distagon ZF2 - 21/2.8, Zeiss Distagon ZF2 - 35/2.0, Nikkor 85/1.8G, Sigma 50/1.4. Nikon x1.4 TC, Sigma x2.0 TC
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Old Feb 2, 2012, 1:59 AM   #14
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Got it, thanks fella!
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Pentax K-7
Tamron 90mm SP Di Macro
Tamron Adaptall 2 - 28mm, 28-80mm, 500mm Mirror
Pentax KAF - 18-55mm WR, 28-105mm PowerZoom
Pentax K - 50mm f/2, 50mm f/1.7, 28mm f/2.2
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