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09-14-2015, 02:13 PM   #1
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FF in crop mode for astro

Assuming the FF can do crop mode, it would make sense (if the pixels are larger) for the FF to produce better results in low light and therefore astro

Regardless the FA 31mm + FF should be interesting for astro

your thoughts?

09-14-2015, 02:51 PM   #2
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Not sure why you'd want to crop; a FF sensor utilized to its fullest works wonders for astrophotography. The 31mm would indeed be a nice wide lens to use for starscapes.

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09-14-2015, 03:52 PM   #3
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Even in crop mode the pixels will still be exactly the same size.
09-15-2015, 02:55 AM   #4
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QuoteOriginally posted by Adam Quote
Not sure why you'd want to crop; a FF sensor utilized to its fullest works wonders for astrophotography. The 31mm would indeed be a nice wide lens to use for starscapes.
My widest glass is crop - 15mm DA, 16mm Samyang f2

Next widest is the FA 31

---------- Post added 09-15-15 at 10:58 AM ----------

QuoteOriginally posted by VoiceOfReason Quote
Even in crop mode the pixels will still be exactly the same size.
Talking about the pixel size physically on the sensor, should be a different number of microns to the K-3 ii for instance... the question is how much different and bigger

09-15-2015, 06:12 AM   #5
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QuoteOriginally posted by Conqueror Quote
Talking about the pixel size physically on the sensor, should be a different number of microns to the K-3 ii for instance... the question is how much different and bigger
The ISO advantage you get is mostly because of the larger area of the FF sensor, cropping to APS-C would make ISO performance equal of APS-C sensors.

A 24MP FF sensor cropped to APS-C (10MP) would give you same level of noise as on Pentax K-3 II.
Or a full 24MP FF images would give you similar noise level on ISO 6400 as you get on a Pentax K-3 II at ISO 3200 as the FF sensor is 2.25 as big as the APS-C sensor in K3 II.

If the generation of the sensors differ much it would of course alter the mix as sensor performance improves over time.
09-15-2015, 08:29 AM   #6
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Exactly what the gentleman above me said. A cropped FF is the same as an APS-C if the pixel pitch is identical. If it's higer, then you get less noise per pixel, but that could be countered by scaling the APS-C image down. So, no - it doesn't help you unless you use the full sensor area.
09-15-2015, 10:36 AM   #7
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31mm is a little long, in general, for astrolandscapes. If you want to do single exposure astrolandscapes then the 500-rule has you reaching for a fast, wide (below 20mm on FF) and sharp at wide-open MF lens.
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