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Does the A7R have the same Dynamic Range when used in "crop" mode?

Hi,
I apologise if this is a really silly question but was just wondering if the A7R still has the same dynamic range when used in APS-C mode?

I realise that other characteristics change like effective focal length, effective aperture (for D.O.F purposes), file size/output resolution etc etc

I have a situation where I am needing to use this feature but if I lost any dynamic range, then I would look at getting a second lens to provide me with the focal length needed..

Thanks a lot, any information or advice would be greatly appreciated!
 

philip_pj

New member
I would use as low ISO as possible, down to base level of ISO 100, this is the sensor's best setting: 14 stops...the a7s is supposedly 15.3 stops but DxO tests will be good to see, for corroboration.

Every stop in ISO (say 100 > 200) drops DR substantially, and all other measures too.
 
Thanks for that, yep, was aware that D.R drops off as you increase the ISO..

Just didn't know whether by using a smaller section of the sensor you lose DR as I often see that dedicated smaller chip cameras have less DR.

This obviously lies somewhere in the manufacturing process and is due to the pixel size.. Or something like that :)
 

GlenC

Member
I came across this web site some time ago when I had the same question. There are a lot of links on the home page that go into much more detail but here is a link that compares the dynamic range for FX and DX formats (for a Nikon D800) vs ISO. According to the author the dynamic range is not the same. I think some old fashion experimenting is needed to confirm this.

Photographic Dynamic Range versus ISO
 
Hi,

I am definitely no authority on the matter as I am the one that asked the question.. :)

Are you talking about comparing different cameras? FX vs DX?

I am talking about the same sensor, just used a smaller portion of it in crop mode..
 

GlenC

Member
The chart compares the same camera (Nikon D800, though I know you asked about the A7R, but I think the sensors are very similar) and plots it's DR vs ISO for both FX and DX modes. Looking at the plots you can see the FX mode has higher DR compared to the DX mode.
 
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