GH4, G9, RX10 IV comparison at ISO 6400

ThePhilosopher wrote:

Androole wrote:

To my eyes there is certainly more detail in the G9 shot than the others (you can see it most clearly in the text on the label).

What I see (my untrained eyes) in most of the images is just trade offs between keeping detail versus NR. However, no real big difference in sensor capability. Hence, if one uses RAW (which I did some basic tests) and the tuning is done right one will get equivalent images. I expected the G9 to be a bit better than it is based on the reviews I read and that was all I was really trying to let others know in case they are considering an upgrade from the GH4. There are other tech features like the 6K photos, additional function buttons, etc.. that obviously make a difference, but image quality will be similar.

I try not to pixel-peep JPEGs, though, since a) I would always be disappointed and b) for me, JPEGs are only for quick sharing, not for photos that I really care about. Obviously you should tailor your tests for your specific usage, though, and if you mainly prefer the output of JPEGs, that is what matters.

The problem is if you do a slide shows on a large screen HDTV sometimes the image can look really bad. Yes, it can be cleaned up with processing, but I was surprised it was so similar.

Yes, RAW is used for my photos I really care about or in challenging conditions in which I am unsure if I can get "exposure" right. However, I have found that modern JPG engines are pretty good if the "exposure" is right for my 90% casual photos.

However, the fact that the G9 is at 1/250s instead of 1/200s means that you are giving up 1/3 stop of light. While 1/3 stop is not particularly noticeable, when comparing sensors that are nominally 2/3 to 1 stop apart, it obviously degrades that difference significantly.

True. But I also have shots at 1/200 and they look identical.

If the shots at 1/200s look identical to the shots at 1/250s, the only conclusion can be that small differences in image quality - real though they absolutely are - are not important to you.

You are your own biggest critic and the only reviewer that matters for your photography. If you can't notice the quality difference, that's an important observation and should usefully inform the future choices that you make with your gear.

But make no mistake, there is a 1/3 stop difference between exposures made with 1/200s and 1/250s. It is exactly the same as saying that ISO 6400 and ISO 8000 look identical.

As you say, your test was not intended to be scientific, but an easy way to improve the consistency and validity of your results is to just put the cameras in M mode and shoot with the exact same settings. If the brightness is different, you can match that in post to see the ramifications on image quality. At least that way you know you are giving the cameras the same amount of light. No need for guesswork, then.

Absolutely. However, for my quick test I was also trying to see what SS the cameras would chose. I typically shoot in A mode and let the camera choose the appropriate shutter, hence my initial intent in this test was really just to see how the cameras behaved in my typical shooting method. Doing my test this way helps me to confirm that the ISO being reported is actually comparable. For some cameras you find there is a large difference, which typically leads me to believe a bit of cheating on the ISO reporting. For instance, if ISO 6400 and A3.5 gave a SS of 100 you might conclude that ISO 6400 is really ISO 3200 or ISO 1600. What matters to me is given an aperture of 3.5 what is the maximum shutter speed I can achieve with acceptable noise level. In fairness I was also testing a few other lenses like the adapted Tamron 16-300 to see if the reported fstop with the adapter was correct.

For a true comparison (in my opinion) it becomes more complicated then just using M mode with the same "settings". For instance, if you want to get the same DOF so you can really compare that the image will be identical, then you need to adjust the aperture. Of course this leads to needing a different SS to get the same light. Is equivalence the same settings or the same image? What about my comment above in which camera manufacturers cheat on ISO? Ultimately for me, it comes down to how the camera behaves in real conditions.