Why does my full frame A7rII show no exposure improvement over my GH3

[ilia_isakov]

<p>Hi, I've owned a panasonic GH3 for the past year. as you may know that camera has a micro four thirds sensor. about a month ago i purchased a sony a7rII from Korea on ebay. new and packaged. But I soon realized that this camera does not handle itself better in low light. It handles noise much better. But people say that a full frame camera has about 2 stops more of light cause of the area of the sensor, which is about twice that of the four thirds one. I took two images to compare, at jpeg, both imported into lightroom and exported out and uploaded here. I admit the WB is a bit umatched, but its still not a sufficient reason for why this camera shows such slight improvement in low light performance under the same settings as a four thirds sensor. Both were shot with 50mm lenses (my 25mm on the gh4) and were set to multi metering mode<br>

the settings on both are:<br>

ISO 2000<br>

f2.0<br>

1/30<br>

this is my Sony full frame <br>

<img src=" alt="" /><br>

this is my Panasonic micro 4/3<br>

<img src=" alt="" /></p>

<p>DID I GET A FAULTY COPY OR IS THIS NORMAL (yes i do see about 1/3-1/2 stop difference)</p>

 

[Jochen_S]

<p>The links don't show up.<br>

My Leica FF generates less visible noise than my old Pentax. But maybe the differences become more obvious when you shoot at even higher ISO? also keep in mind that FF eats 2 f-stops to generate the same DOF as MFT. <br>

Also take the pixel count into the comparsion and figure out how high you can crank your Sony's ISO till a picture looks as bad as taken with the GH3 at the same output size.</p>

[ilia_isakov]

<p>sorry, about that. Here is the link. 1st photo is sony. 2nd photo is micro four thirds.<br>

<img src="http://www.eli.camera/photo.html" alt="" /><br>

http://www.eli.camera/photo.html.<br>

can you send me an article where it says that a full frame eats 2 stops to achieve the same DOF as a four thirds camera?</p>

[Jochen_S]

<p>Sorry no link at hand, but either look at the engraved DOF scales of a pair of heritage lenses with focal length relation 1 : 2 - like 24 & 50mm or use one of the posh modern online calculators: http://www.dofmaster.com/dofjs.html for comparsion.</p>

[andylynn]

<p>It's hard to tell what's going on here, looking at these small JPGs, so I'm going to give a few general comments and hope they answer your questions.</p>

<p>When we say that a full frame camera has 2 stops better light gathering than a M4/3, that really translates to better quality when using a higher ISO. If you use the same settings (ISO, aperture and shutter) on both cameras, your exposures should come out very similarly. ISO is a standard measure that is not dependent on sensor size. The advantage of the full frame is that if you compared a shot from the Sony at ISO 8000 to a shot from the Panasonic at ISO 2000 you should see similar quality. This means that when using the Sony you could stop the lens down and/or increase the shutter speed, and compensate with higher ISO.</p>

<p>You won't see all the advantages of a higher end camera when shooting JPG. If you want to see the most image detail and dynamic range you need to use raw. There are many different metrics involved in the broad concept of "image quality", and a lot of these can be traded off. For example, if you have a noisy high ISO shot and you apply strong noise reduction you will be trading detail for low noise. A lot of cameras are set to use strong noise reduction by default in the JPGs, so that if you look at, for example, an ISO 6400 shot from a small sensor camera, at first glance you might think it has good "image quality" because it got decent white balance and has almost no noise. But if you look closer you might see that there's very little detail, lots of smudging and surfaces that look "waxy". A large sensor camera might take the same shot with very little noise to start with, so that strong noise reduction is not needed, and while the resulting images from the two cameras would be similar in that they have low noise, the large sensor shot would show much more detail and realistic textures. In order to see this relationship between detail, texture and noise reduction, you would have to load a raw file into software that has noise reduction adjustments, look at the effects of different settings, and then judge for yourself what settings to use.</p>

<p>With Sony, you can download a free copy of Capture One and use it for raw files. This does have a learning curve, but it's very powerful. The free copy only reads Sony raw files.</p>

[ilia_isakov]

<p>Thank you. Yes, i've tested these in Raw and saw plenty of difference in both improved noise and brighter and cleaner image with my full fram over the micro four thirds one.</p>

[ramin m]

<p>FF sensor is not twice bigger than a m4/3 sensor. It has in fact nearly 4 times more area (it is precisely 3.84 times larger). Two 'stops' of more light actually means 4 times more light hitting the sensor! Light stops (EV) are defined to have a logarithmic curve not a linear one.<br /> The exposure is not directly a function of the total amount of light the sensor receives. It is in fact about the intensity of light per unit of area and that is not affected by the sensor size: larger sensor receives more light but that light is distributed over a larger area so for the same scene and level of available light, exposure is not affected by the size of the sensor. People who say to the contrary of the above, have simply come to believe a fallacy.<br /> If for the same ISO, aperture and shutter speed settings (a certain given exposure setting), you have still observed a difference in the brightness level of the pictures taken with your m4/3 and and with your FF camera, it simply means the manufacturers have not followed the same standard when they were setting up the exposure levels of their camera models. They may do it for their own reasons speculating of which is not the point of this discussion.<br /> Your Sony FF camera has better low light performance than your m4/3 camera which means in high ISO settings you will observe noticeable difference in the noise that is present in the picture. That is the advantage of your FF camera.</p>