Michael Reichmann's take on smaller full frame Sony FE mount lenses

Started Dec 18, 2013 | Discussions thread
Lab D Veteran Member • Posts: 6,938
Re: Right, for DR usually only 1/2 stop difference.

Erik Magnuson wrote:

Lab D wrote:

The theoretical is 1.94 stops. The A7r sensor 30dB noise threshold is merely 1.86 stop better

But as you know it varies for different ISOs and overall it is not 2 stops (and you agree).

More light collection capability is not very important when there is plenty of light. Above ISO 800 -- where mid-tone noise is a photographic factor -- it's closer to two stops than any other 1/3 stop choice. Since we can't effectively control exposure finer than 1/3 stop, 2 stops is the best number to use.

I think you are cherry picking.  When I comapre the EM1 to the A7 I don't see what you are seeing and I do see only a 1 stop difference in DR at most ISOs.

For example, for the EM1 at ISO800 we get 30dB and for the A7 at ISO2300 we get slightly UNDER 30dB.   For your 2 stops claim that should be ISO3200.   Even the A7R is not 3200 for 30dB and closer to ISO2400 and not ISO3200.

What is funny is for most ISOs DR is only about 1/2 stop!  I didn't know that until I looked.  That blows a big hole in to the 2 stops claim.

So again overall for most measurements there is LESS than a 2 stops difference and for for some only 1/2 a stop.  The BEST you can find is 1.9 stops, but most are far less, so why claim 2 for everything??

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