Reading mode: Light Dark

A77 mk2 ISO weirdness??

Go to last post
B

bwigg

Senior Member
Messages
1,250
Reaction score
50
Location
US
Is there something strange up with the new A77 mk2 ISO speeds?

I haven’t had a lot of time to compare my new mk2 to the old A77, but I have noticed about a one stop difference in ISO speeds between the two.

My description may be a little confusing but for instance if I leave both in P mode using the same ISO the mk2 uses ½ the shutter speed compared to the A77.

For example, using an outdoor target in aperture mode I selected ISO 200, F/6.3 on both cameras and the A77 used a shutter speed of 1/320. The mk2 used 1/160 for the same exposure.

I changed to auto ISO and both cameras used the same shutter speed, but the mk2 chose ISO 400 vs. ISO 200 on the A77.

I used an indoor target so I could control the lighting conditions and changed to manual mode. I then discovered I needed to make a one stop adjustment in either ISO or shutter speed to obtain the same exposure.

With the indoor example I needed a shutter speed of 1/50, ISO 3200 at F6.3 to obtain the same exposure that the A77 had at 1/100, ISO 3200 at F6.3.

I made these tests using the same Sony 18-250mm lens to rule out variations in the lenses.

My conclusion is the ISO rating on the mk2 is one stop different from the old A77. For example ISO 3200 on the mk2 is equal to ISO 1600 on the old A77.

Has anybody else noticed this or is my particular example of the mk2 a little off?
 
bwigg said:
Is there something strange up with the new A77 mk2 ISO speeds?

I haven’t had a lot of time to compare my new mk2 to the old A77, but I have noticed about a one stop difference in ISO speeds between the two.

My description may be a little confusing but for instance if I leave both in P mode using the same ISO the mk2 uses ½ the shutter speed compared to the A77.

For example, using an outdoor target in aperture mode I selected ISO 200, F/6.3 on both cameras and the A77 used a shutter speed of 1/320. The mk2 used 1/160 for the same exposure.

I changed to auto ISO and both cameras used the same shutter speed, but the mk2 chose ISO 400 vs. ISO 200 on the A77.

I used an indoor target so I could control the lighting conditions and changed to manual mode. I then discovered I needed to make a one stop adjustment in either ISO or shutter speed to obtain the same exposure.

With the indoor example I needed a shutter speed of 1/50, ISO 3200 at F6.3 to obtain the same exposure that the A77 had at 1/100, ISO 3200 at F6.3.

I made these tests using the same Sony 18-250mm lens to rule out variations in the lenses.

My conclusion is the ISO rating on the mk2 is one stop different from the old A77. For example ISO 3200 on the mk2 is equal to ISO 1600 on the old A77.

Has anybody else noticed this or is my particular example of the mk2 a little off?
Click to expand...
I'll have to test it out myself to confirm. I was already expecting a potential difference in exposure settings between the two, but not a full stop. I was expecting maybe 1/3 to 1/4 stop difference.

Are you shooting in RAW or JPEG? Was DRO turned on?

Does your exposure between the two images look identical or does one look over/under exposed?

How does the histrogram look between the two?
 
DXO measured the ISO of the A77MKII to be just a bit lower than the A77 at each setting not, higher.
 
VirtualMirage said:
VirtualMirage said:
Are you shooting in RAW or JPEG? Was DRO turned on?
Click to expand...
Click to expand...
I was using JPEG with DRO off.
VirtualMirage said:
Does your exposure between the two images look identical or does one look over/under exposed?
Click to expand...
They are very close. Except if I use the exact same settings on the mk2, then the mk2 is underexposed compared to the A77.

For example using my earlier scenario, if I set the A77 to 1/100, f6.3 and ISO 3200 it looks fine on the A77. Using the same settings with the mk2 I get under exposure.

If I adjust the mk2 to 1/50 on the shutter speed they look pretty close.
VirtualMirage said:
How does the histrogram look between the two?
Click to expand...
I haven't really looked.

 
K E Hoffman said:
DXO measured the ISO of the A77MKII to be just a bit lower than the A77 at each setting not, higher.
Click to expand...
The measured ISO is lower, which means the indicated ISO is more "optimistic". This would lead to needing a higher ISO setting on the A77II to get the same exposure. The difference is less than 1/3 stop, so that's not an explanation. Strange, indeed. My Fuji X-E1 was off 0.3 to 0.5 stops vs the A77.

http://www.dxomark.com/Cameras/Comp...lpha-77-II-versus-Sony-SLT-Alpha-77___953_734
 
bwigg said:
Is there something strange up with the new A77 mk2 ISO speeds?

I haven’t had a lot of time to compare my new mk2 to the old A77, but I have noticed about a one stop difference in ISO speeds between the two.

My description may be a little confusing but for instance if I leave both in P mode using the same ISO the mk2 uses ½ the shutter speed compared to the A77.

For example, using an outdoor target in aperture mode I selected ISO 200, F/6.3 on both cameras and the A77 used a shutter speed of 1/320. The mk2 used 1/160 for the same exposure.

I changed to auto ISO and both cameras used the same shutter speed, but the mk2 chose ISO 400 vs. ISO 200 on the A77.

I used an indoor target so I could control the lighting conditions and changed to manual mode. I then discovered I needed to make a one stop adjustment in either ISO or shutter speed to obtain the same exposure.

With the indoor example I needed a shutter speed of 1/50, ISO 3200 at F6.3 to obtain the same exposure that the A77 had at 1/100, ISO 3200 at F6.3.

I made these tests using the same Sony 18-250mm lens to rule out variations in the lenses.
Click to expand...
You also used same focal length on the zoom for both right? Sorry for such a trivial question but I had to ask. Your test shows the numbers going in the wrong way for the m2. If this is the case, it is a deal breaker for me. I respectfully hope you missed something on your test.
bwigg said:
My conclusion is the ISO rating on the mk2 is one stop different from the old A77. For example ISO 3200 on the mk2 is equal to ISO 1600 on the old A77.

Has anybody else noticed this or is my particular example of the mk2 a little off?
Click to expand...
 
9000AF said:
K E Hoffman said:
DXO measured the ISO of the A77MKII to be just a bit lower than the A77 at each setting not, higher.
Click to expand...
The measured ISO is lower, which means the indicated ISO is more "optimistic". This would lead to needing a higher ISO setting on the A77II to get the same exposure. The difference is less than 1/3 stop, so that's not an explanation. Strange, indeed. My Fuji X-E1 was off 0.3 to 0.5 stops vs the A77.

http://www.dxomark.com/Cameras/Comp...lpha-77-II-versus-Sony-SLT-Alpha-77___953_734
Click to expand...
Yeah, I was seeing maybe 1/4 stop difference.
 
migue65 said:
You also used same focal length on the zoom for both right? Sorry for such a trivial question but I had to ask. Your test shows the numbers going in the wrong way for the m2. If this is the case, it is a deal breaker for me. I respectfully hope you missed something on your test.
Click to expand...
How are they going the wrong way?

Secondly, why would it be a deal breaker? ISO is just a film standard being converted to a digital world to give photographers a way to better interpret gain.

If ISO 200 on the A77II looks as good or better than ISO 100 on the A77, same goes for ISO 3200 versus the A77's ISO 1600, when using the same values elsewhere, why does it matter?

The only impact, at worst, that will do is you will have to mentally remember that the A77II can and may need to go one ISO stop higher than the A77 but that doesn't mean it will be up to one stop noisier than the A77. While not exact, it's similar to the mentality for some of those that go from APS-C to Full Frame: they used to think they could go no higher than ISO 1600 and that thought carries over to their full frame, when in actuality they can go much higher in ISO and not degrade in image quality as much as they thought.
 
migue65 said:
You also used same focal length on the zoom for both right? Sorry for such a trivial question but I had to ask. Your test shows the numbers going in the wrong way for the m2. If this is the case, it is a deal breaker for me. I respectfully hope you missed something on your test.
Click to expand...
Yes I used the same focal length. I will try to repeat the tests as time permits.
 
What will be interesting is to see how it compares to the D7100. If one was to go by DxO's ISO measurements, the A77II and the D7100 are just about identical.

And going from past observations, at any same ISO and aperture, the D7100 tended to use a slightly longer shutter speed than the A77.
 
I did try a very quick test with my D7100 and the shutter speed fell in-between the two for about the same exposure.

The D7100 needed 1/80 as compared to 1/50 on the mk2 and 1/100 with the A77. I did not factor the D7100 in the equation as I was using a different lens and that could account for some difference.
 
Please check the Apertures also. I am in the office. Thus, I can't do the test.
 
I used F/6.3 for all tests.

If time permits I will try again tonight and try to posts the results. I am at work, so I do not have access to any images at the moment.

This a observation and not a complaint against the A77 mk2.

I also noticed on Imaging Resources comparometer a difference in shutter speed at the same ISO examples, but not quite as drastic as mine.
 
bwigg said:
I used F/6.3 for all tests.

If time permits I will try again tonight and try to posts the results. I am at work, so I do not have access to any images at the moment.

This a observation and not a complaint against the A77 mk2.

I also noticed on Imaging Resources comparometer a difference in shutter speed at the same ISO examples, but not quite as drastic as mine.
Click to expand...
Me too. When I get home I will test with my A57. My A77 was already sold and shipped. What I noticed on the A77II was the aperture(s). I could be wrong.
 
It is going in the wrong way because I would have to cut my ss in half or double the sensitivity to get the same exposure I get with my a77 now. that in turn increases digital noise. I use my a77 for wildlife with budget lenses that are only good at around f8- f11 and i need to get to 1/1000 at least.

Or ...did I misunderstand the results?
 
migue65 said:
It is going in the wrong way because I would have to cut my ss in half or double the sensitivity to get the same exposure I get with my a77 now. that in turn increases digital noise. I use my a77 for wildlife with budget lenses that are only good at around f8- f11 and i need to get to 1/1000 at least.

Or ...did I misunderstand the results?
Click to expand...
 
bwigg said:
bwigg said:
bwigg said:
Are you shooting in RAW or JPEG? Was DRO turned on?
Click to expand...
Click to expand...
I was using JPEG with DRO off.
bwigg said:
Does your exposure between the two images look identical or does one look over/under exposed?
Click to expand...
They are very close. Except if I use the exact same settings on the mk2, then the mk2 is underexposed compared to the A77.

For example using my earlier scenario, if I set the A77 to 1/100, f6.3 and ISO 3200 it looks fine on the A77. Using the same settings with the mk2 I get under exposure.

If I adjust the mk2 to 1/50 on the shutter speed they look pretty close.
bwigg said:
How does the histrogram look between the two?
Click to expand...
I haven't really looked.
Click to expand...
Perhaps a trivial question but I'm not sure about how you judged "well exposed" and "under exposed" in your comparisons so if you used your camera's EVF or LCD is there any chance that one camera is NOT set to show the actual exposure simulation? So on one perhaps you wouldn't get WYSIWYG?

Another point to check would be whether there's any typr of manual exposure compensation set. And finally it might be useful to compare histograms and exposure data as EV.
 
Then this would still be a deal breaker for me as there was not real improvement in digital noise control compared to my a77 and therefore no need to spend the money. If this is true, the 20% improvement is marketting spin.
 
You must log in or register to reply here.

Keyboard shortcuts

f
Forum
m
My threads
Mobile site
About
Editorial content
Cameras & Lenses
Community
All content, design, and layout are Copyright © 1998–2025 Digital Photography Review All Rights Reserved.
Reproduction in whole or part in any form or medium without specific written permission is prohibited.
When you use DPReview links to buy products, the site may earn a commission.
©GPS Media - Guides, Products, Services.
Back
Top