Stack Promaster 1.7X + Pentax 1.4X (2 imgs)

Started May 12, 2014 | Discussions thread
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brandrx Forum Pro • Posts: 28,337
Stack Promaster 1.7X + Pentax 1.4X (2 imgs)

Hi folks,

FWIW: I stepped outside with the Pentax K-3 this morning and took a few test shots using the Promaster 1.7X Pz_AF Spectrum 7 + Pentax 1.4X HD AW. I used the Sigma 300mm f2.8 and the Pentax DA*60-250/4 lenses. I took about ten shots with each lens.

With the Sigma 300/2.8 - Works good. Locked focus on all targets. I wouldn't hesitate to use this combo in some real shooting.

With the Pentax DA*60-250/4 - Works fair. On a couple of the targets I had to prefocus the lens to near focus before the lens would autofocus to lock. I probably would not use this combo myself in real shooting.

Since the Promaster 1.7X Pz_AF has previously been shown to be closer to 1.5X then multiply the focal length and aperture in the EXIF by 1.5X to get the proper reading.

Pentax K-3 + Promaster 1.7X + Pentax 1.4X HD AW + Sigma 300/2.8

Pentax K-3 + Promaster 1.7X + Pentax 1.4X HD AW + Pentax DA*60-250/4



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Ron - 'We don't have time to go take pics this afternoon Carl.'
Carl - 'What do you mean? It will only take 1/1000s.'
'Keep your eyes looking forward. However, glance back now and then to see where you've come from. It will put a smile on your face.' ~ brandrx

Pentax K-3
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