Reading mode: Light Dark

A7R III Low Light Focusing Question

Go to last post
T

Tommygun45

Senior Member
Messages
1,392
Solutions
3
Reaction score
608
So I am a professional real estate photographer and have a three year old. I have been using a D750 for this task for a few years now and it is excellent. I got an A6500 as a backup and use it on vacations/trips etc. The video is great too. But now I have two systems. I want to move to a (two camera) one system setup and get the A7rIII but am curious about its low light focusing.

I love my A6500 but hate feeling like I am compromising IQ when using it compared to the D750. I am a pixel peeper and a gear nerd so this stuff does matter to me. Before the Nikon I was an A6000 guy but left the system due to its inability to focus in low light. Having a fast moving toddler and doing more and more things in dim conditions I want a camera that can handle high ISO noise AND focus in Low light as good as my D750, but has all of the features of the Sony eco system.

So my question is, I remember reading that the A7rIII will focus down to -4 but only with F2 lenses. Does this mean the Sony will NOT focus to -4 with, say, the 24-70 2.8 GMaster? These are just some shots I took last night. I want a more well rounded camera that can do this, shoot 4k video, eye af etc. Is the A7RIII capable of these kinds of shots? Or will it be? What do we think?

























There were 8 or so shots that were all perfectly in focus as this fast 6 year old was sprinting in incredibly dark conditions. Impressive.









 

Attachments

  • 3696984.jpg
    3696984.jpg
    2.5 MB · Views: 0
  • 3696990.jpg
    3696990.jpg
    2.4 MB · Views: 0
  • 3696989.jpg
    3696989.jpg
    754.8 KB · Views: 0
  • 3696987.jpg
    3696987.jpg
    634.5 KB · Views: 0
  • 3696986.jpg
    3696986.jpg
    1.1 MB · Views: 0
  • 3696985.jpg
    3696985.jpg
    1.2 MB · Views: 0
As a background, I have shot extensively with D810's and 5DSR's, and now, A7RII's and the A9.

With the Sony cameras, I have learned to take their low light focusing specifications 'with a grain of salt' (with the exception of the A99II, which in my experience, focuses more like a DSLR). My A9 focuses quite well in low-light, but my DSLR's always seemed to focus just slightly more reliably in really low-light conditions. I expect that the A7RIII will be similar to the A9, but of course, I will not know with certainty for another month, when my A7RIII arrives.

Of course, the position of your subject in the frame will make a difference, given the type of sensor being utilized (cross-type, etc). There are a lot of variables at play, here.

Based upon the photos you posted, I would rent the Sony camera before you make your decision.

--
Jeff
Florida, USA
http://www.gr8photography.com
 
Last edited:
I want to get back into underwater photography and the cost of a housing means sticking with a camera for a good while. Id get the sony a7riii if it has good low light focus even with adapted lenses since sony does not have a fish eye lens yet. Underwater its dim and I stop down the lenses quite a bit to get good depth of field. I wonder how it compares to dslr's. My last underwater camera was the canon t2i.
 
Tommygun45 said:
Is the A7RIII capable of these kinds of shots? Or will it be? What do we think?
Click to expand...
Regarding the a9, its AF very capable in low light. If you haven't already seen it, check out the video at:


In particular, take a look at the second starting at 19:35, where they are testing low light focus and comparing results from the a9 and D5 cameras.

We don't yet know how well the low light focus behavior of the a7R3 compares to the a9. It has fewer Phase detection points, but far more contrast detection points, and its slightly higher DR and much higher resolution all bode well for low light AF capability being at least comparable IMO.
 
SilvanBromide said:
Tommygun45 said:
Is the A7RIII capable of these kinds of shots? Or will it be? What do we think?
Click to expand...
Regarding the a9, its AF very capable in low light. If you haven't already seen it, check out the video at:


In particular, take a look at the second starting at 19:35, where they are testing low light focus and comparing results from the a9 and D5 cameras.

We don't yet know how well the low light focus behavior of the a7R3 compares to the a9. It has fewer Phase detection points, but far more contrast detection points, and its slightly higher DR and much higher resolution all bode well for low light AF capability being at least comparable IMO.
Click to expand...
 
paulnelson88 said:
SilvanBromide said:
Tommygun45 said:
Is the A7RIII capable of these kinds of shots? Or will it be? What do we think?
Click to expand...
Regarding the a9, its AF very capable in low light. If you haven't already seen it, check out the video at:


In particular, take a look at the second starting at 19:35, where they are testing low light focus and comparing results from the a9 and D5 cameras.

We don't yet know how well the low light focus behavior of the a7R3 compares to the a9. It has fewer Phase detection points, but far more contrast detection points, and its slightly higher DR and much higher resolution all bode well for low light AF capability being at least comparable IMO.
Click to expand...
Click to expand...
 
SilvanBromide said:
paulnelson88 said:
SilvanBromide said:
Tommygun45 said:
Is the A7RIII capable of these kinds of shots? Or will it be? What do we think?
Click to expand...
Regarding the a9, its AF very capable in low light. If you haven't already seen it, check out the video at:


In particular, take a look at the second starting at 19:35, where they are testing low light focus and comparing results from the a9 and D5 cameras.

We don't yet know how well the low light focus behavior of the a7R3 compares to the a9. It has fewer Phase detection points, but far more contrast detection points, and its slightly higher DR and much higher resolution all bode well for low light AF capability being at least comparable IMO.
Click to expand...
Click to expand...
Click to expand...
 
My extremely limited experience with the a7RIII leads me to believe it is as good or better than my a7RII... Sony says its an EV better. Its definitely quicker.

Here is a post discussing this...although ignore the first paragraph. It's a low-light focusing example from my a7RII at (probably) an EV LESS than your examples (w/ f4.0 APS-C zoom lens), although nothing was moving:

https://www.dpreview.com/forums/post/60247628

Bruce

--
http://www.pbase.com/misterpixel
 
Last edited:
What mode do you use to shoot in low light? Does face detection and eye detection work as well in low light as they do in regular light? The reason I posted this in the first place is from this account. Maybe the thinking is if you are shooting in low light youll be using a fast lens anyways.

From dpreview.

Like with the a9, Sony has updated its low light AF rating, ensuring focus down to -3 EV with F2 lenses. Indeed, we've found Sony's ratings to be relatively accurate, with a F1.4 lens offering 1 stop faster performance (down to -4 EV), but slower lenses offering worse performance (-1 EV for F4 lenses). The a7R II predecessor focused down to -3 EV with F1.4 lenses,and reliably to -2 EV with F2 lenses.
 
I think the problem is that it's mirrorless and hence lacks separate focusing sensors. The focusing sensors on a reflex camera are separate from the image sensor itself and this allows it have three capabilities that greatly increase low light focusing ability - the pixel size on the sensors can be huge, the sensor pixels are monochrome, and IR assist beams can be used.

Being physically big will give you a huge increase in signal strength from your pixels. On sensor focusing sensors will be stuck at the same resolution as the image sensor itself.

Being monochrome will immediately allow a 3x increase in signal strength compared to colored pixels that are light filtered.

Image sensors have an IR filter to prevent being blown out by bright sunlit scenes. These filters also block IR assist beams. The assist beams on sony's are red, not IR. Separate focusing sensors aren't IR filtered.

So even though the Sony sensors have some of the highest iso sensitivity, the lack of seperate focusing sensors means they have sucky low light focusing abilities.
 
zephyrprime said:
Being higher resolution would make it worse for low light focusing and low light in general.
Click to expand...
Not, as I understand it, for contrast detection. The a7R3 sensor has 425 contrast-detection AF points.
 
Last edited:
zephyrprime said:
I think the problem is that it's mirrorless and hence lacks separate focusing sensors. The focusing sensors on a reflex camera are separate from the image sensor itself and this allows it have three capabilities that greatly increase low light focusing ability - the pixel size on the sensors can be huge, the sensor pixels are monochrome, and IR assist beams can be used.

Being physically big will give you a huge increase in signal strength from your pixels. On sensor focusing sensors will be stuck at the same resolution as the image sensor itself.

Being monochrome will immediately allow a 3x increase in signal strength compared to colored pixels that are light filtered.
Click to expand...
i think that the mirror knocks down something like 50% of the light hitting the pdaf module tho, it's far from ideal... dslr pdaf modules also don't have near as much pdaf coverage; these a9/a7riii cameras can focus just about all the way out to the edge of the frame.
zephyrprime said:
Image sensors have an IR filter to prevent being blown out by bright sunlit scenes. These filters also block IR assist beams. The assist beams on sony's are red, not IR. Separate focusing sensors aren't IR filtered.

So even though the Sony sensors have some of the highest iso sensitivity, the lack of seperate focusing sensors means they have sucky low light focusing abilities.
Click to expand...
not if you use fast glass:

 
These are good photos and not easy to get anything but I'd call some of them out of focus.

My A7RII and Canon 35LII focuses very accurately in light that low and the sharpness would blow you away, the IBIS is just incredible. If the A7RIII is as good to AF with native lenses I'll be really happy.

With DSLRs adding a faster than f2.8 lens isn't supposed to make any difference to the AF. With the Sony the extra stops count. I think it would be worth you trying a A7RIII with a 35/1.4 and making your own mind up.

Cheers, Andrew
 
Jeff2013 said:
As a background, I have shot extensively with D810's and 5DSR's, and now, A7RII's and the A9.

With the Sony cameras, I have learned to take their low light focusing specifications 'with a grain of salt' (with the exception of the A99II, which in my experience, focuses more like a DSLR). My A9 focuses quite well in low-light, but my DSLR's always seemed to focus just slightly more reliably in really low-light conditions. I expect that the A7RIII will be similar to the A9, but of course, I will not know with certainty for another month, when my A7RIII arrives.

Of course, the position of your subject in the frame will make a difference, given the type of sensor being utilized (cross-type, etc). There are a lot of variables at play, here.

Based upon the photos you posted, I would rent the Sony camera before you make your decision.

--
Jeff
Florida, USA
http://www.gr8photography.com
Click to expand...
From what I have read and experienced, A9 still suffers so-called AF stop-down issue while DSLRs don't have. But if you shoot wide open with fast lenses it should be fine such as if you compare A9 with FE 70-200 GM @f2.8 vs 5DsR or D810 with their respective 70-200/2.8 lens @f2.8. Do you stop down a bit? That probably is the cause.

--
https://www.flickr.com/photos/55485085@N04/albums
http://pwphotography.zenfolio.com
 
Last edited:
Two things about AFC tracking for the A7Riii,

The contrast detection seems to be pretty useless for AFC, you get like 50% or less hit rate as it cannot keep up with the FPS.

If you use the phase detection points, its very good. I expect it to be lens dependent though.

Below is shot at similar lighting conditions as yours I think. Maybe the sky is still be bit lighter but the sun has set. A7Riii can track running with 10fps shot with sony 35mm f1.4 za. The last two frames out of 13 were OOF when she got too close.

I used D750 with sigma 35mm f1.4 for two years and I would rate the AF of the sony combo better at AF tracking now. Plus things like eye AF will be very useful.

But there are SOOOO many AF settings on the a7riii so I am trying to figure out which is the best of my use case which is running toddlers/kids. Currently this is set to 10fps although I don't need the 10fps but dpreview say tracking is better at 10fps because they don't have to do live view?? Face detection enabled. Not sure if I should register their faces....

95c9a1b02026498abe4a2f059517b08b.jpg
 
Last edited:
You must log in or register to reply here.

Similar threads

P
Sony A7R V + Tamron 50-400mm - Match made in heaven
Replies
11
Views
12K
PWPhotography
P
R
My Lightweight Travel Photography Kit with Sony A7R V
2 3
Replies
46
Views
11K
Rluizsm
R
Martin Ocando
It happened A7R IV -> A7R V
2
Replies
26
Views
7K
Martin Ocando
Martin Ocando
C
Sony A7R V + 20-70mm f/4 as second body
2
Replies
20
Views
8K
CydeWeys
C
photofan1986
Focusing problems with the Sony A1
3 4 5
Replies
98
Views
20K
Interceptor121
I

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