1DX III vs R5 AF

[Fast Glass]

I have not had an issue with focusing on the stars. I would assume because of the contrast. Even my 1D III or T2i can do that.

I will post a pic of what I was having a hard time. But it was taking a pic of my cat illuminated by the glow of the light in another room.

The exposure was 1/320, 800,000 ISO f/1.4. It was very dark and obviously very little contrast to work with. The 1DX III had no issues and locked on every time but I couldn't get the live view focusing to lock on even once.

Now this is a very extreme example, but probably not so extreme for someone like a photogernalist.

But I am not knocking the AF of the R5, as I believe it has a different version of DPAF and it probably perform better with native RF glass than even EF glass.

Not am I even knocking the live view AF. I view it as another option for focusing and will use it within it's limits. What surprises me is almost no one knows about this. Not even FroKnowsPhoto who did an excellent review on it made mention of the superior AF of PDAF.

[Fast Glass]

I will be getting my hands on the 1DX III soon again along with the 50mm f/1.2, 24-105mm II, 5D IV and 600RT III flash.

So I will be able to do a more in depth comparisons.

[Kayaker72]

Ok. Just played with this on my 5DIV and R5. If I have done the math correctly, your image was -4.67 EV.

Even borrowing our cat for good comparison:
5DIV PDAF would not AF. Not a chance.
5DIV DPAF (live view). Some hunting, but would AF.
R5 Spot AF (DPAF). Definitely struggled, but I did get occasionally AF.
R5 Single Point AF. Some hunting, but fairly good.

I should have tried expanded point AF. Next time.

Next, I tried even darker with the R5, somewhere around -5.5 EV. Spot AF, no go. Single point AF would work. It was slow, needed some contrast, but it would work.

So, my takeaway is more that the PDAF on the 1DX III has impressive low light abilities. Actually outperforming it’s spec. Considering how incredibly dark these rooms were, I am absolutely fine with the R5’s performance.


Sent from my iPhone using Tapatalk

[Fast Glass]

So, my takeaway is more that the PDAF on the 1DX III has impressive low light abilities. Actually outperforming it’s spec. Considering how incredibly dark these rooms were, I am absolutely fine with the R5’s performance. Sent from my iPhone using Tapatalk

Indeed, and it is possible I did something wrong or there are some setting I could have done differently.

But as you said these are incredibly extreme examples and hardly can be considered poor performance if it can't focus. Although I do shoot sometimes in very dark situations. So having this low light capability is actually pretty handy for me.

What was impressive to me was how easy it was to focus. It had no issues whatsoever and it was like another day at the office for the 1DX III. It just blew me away. My 1D III wouldn't even dream of focusing at such low light levels. So the fact it didn't focus in live view didn't disappoint me, but it sure as hell shocked me when in PDAF it just locked on with no issues.

But it is good to know the R5 seems to do better at least in the low light department.

Funny how our pets becomes our test subjects.

[Fast Glass]

I guess my bigger deal is not that DPAF didn't focus in ridiculously low light. Or if it is even ussuable for different applications. As a whole DPAF didn't live up to PDAF. And in my view with all the hype surrounding mirrorless bodies, it becoming the future and making DSLR's obsolete. It needs to at least match or very nearly so what DSLR's are capable of. And when you are talking about flagship products that is a high bar to clear indeed.

Granted I didn't have a side by side experience with the R5. So the verdict is still out.

And the R5 is not the same thing as the 1DX III. It is not the flagship to flagship comparison. When they finally release a flagship mirrorless I will be extremely interested in that.

Because right now in less than a year I will probably be buying the 1DX III or if it makes sense to go with a mirrorless flagship if/when that becomes a reality.