Why go full frame?

[MitchP]

It depends on what you're shooting. For wildlife telephoto I prefer my Canon R7 for more "reach" and high MP count. Also the autofocus is wonderful for wildlife. For wide angle I prefer my old Sony A7RII with wide angle lenses for better light gathering and wider perspective. I usually manually focus landscapes anyway. If I was doing an event I'd take the R7 just for the advanced autofocus. APS-C has always been a problem ie: noise, but modern software makes that argument a little moot.

 

[slat]

I like most everything about a canon R7 but would like something better in low light. I could do the R5 and use the crop function but think for just a little more money I could do the Canon R6 Mark ii and the Canon R7. Fewer MP on the full frame R6 mark ii but more MP on the R7.

 

[Ysarex]

I like most everything about a canon R7 but would like something better in low light. I could do the R5 and use the crop function but think for just a little more money I could do the Canon R6 Mark ii and the Canon R7. Fewer MP on the full frame R6 mark ii but more MP on the R7.

The low light advantage of the R5 comes from the larger area of the FF sensor so if you engage the crop function in the R5 it becomes an APS-C sensor camera and looses it's low light advantage. Look at this graph on Photons to Photos -- the R7 and R5(APS-C) plots pretty much overlay. No low light advantage from the R5 in crop mode. DR graph

 

[slat]

I realize that. I would probably only use the crop function when shooting wildlife. Otherwise I would probably be in FF.

 

[Ysarex]

I realize that. I would probably only use the crop function when shooting wildlife. Otherwise I would probably be in FF.

Got it.

 

[AlanKlein]

The low light advantage of the R5 comes from the larger area of the FF sensor so if you engage the crop function in the R5 it becomes an APS-C sensor camera and looses it's low light advantage. Look at this graph on Photons to Photos -- the R7 and R5(APS-C) plots pretty much overlay. No low light advantage from the R5 in crop mode. DR graph

I realize that. I would probably only use the crop function when shooting wildlife. Otherwise I would probably be in FF.

How does a camera change the sensor elements when switching from FF to the crop function? Aren't you just taking a smaller section of the only sensor in the camera?

 

[Ysarex]

How does a camera change the sensor elements when switching from FF to the crop function? Aren't you just taking a smaller section of the only sensor in the camera?

Yep, same sensor -- you're just using a smaller section of that same sensor.

So why does the low light performance degrade when you crop the sensor area? Because the SNR (signal noise ratio) worsens with a decrease in sensor area. The smaller sensor collects less total light. reference: Sensor size and SNR

 

[AlanKlein]

Yep, same sensor -- you're just using a smaller section of that same sensor.

So why does the low light performance degrade when you crop the sensor area? Because the SNR (signal noise ratio) worsens with a decrease in sensor area. The smaller sensor collects less total light. reference: Sensor size and SNR

But that article compares sensors of different sizes. Yes, larger sensors capture more light easier lowering SNR. But the sensor in a single camera does not change size. Each element of the sensor stays the same in area. The crop mode is just capturing a smaller number of sensor elements lowering the resolution. But each sensor element is still the original area. The SNR would be the same. Am I missing something?

 

[smoke665]

he crop mode is just capturing a smaller number of sensor elements lowering the resolution. But each sensor element is still the original area. The SNR would be the same. Am I missing something?

My understanding is that there is no difference in light gathering ability at the pixel level. The SNR increase is because the total light collected on the frame is less.

 

[407370]

My new Z8 was a retirement present from me to me.

I have never owned a high end camera before and Z8 has opened my eyes to what is possible with ease compared to cameras that cost 1/10 of the Z8.

My photography is technically and spiritually better because I can get better results with much less effort.

I can now get pictures that I could not get with my old gear. I can actually get an in focus picture of things that move.

The low light performance is 1000% better than what I am used to. Sunrise / Sunset pics with foreground details that I can bring up in post.

I now have 45Mp to play with. I now plan to centralise a subject knowing I can crop with no effect on the final image.

APSC is good enough but full frame to me is just better.

CHEERS
JBO

 

[Ysarex]

But that article compares sensors of different sizes.

If you switch a camera into crop mode you effectively have a different size sensor. The area of the sensor outside the cropped center is no longer part of the captured image.

Yes, larger sensors capture more light easier lowering SNR. But the sensor in a single camera does not change size. Each element of the sensor stays the same in area. The crop mode is just capturing a smaller number of sensor elements lowering the resolution. But each sensor element is still the original area. The SNR would be the same. Am I missing something?

SNR is not only a function of sensel size but also of total light captured by the sensor independent of the sensel size. Look at these two DR plots at Photons to Photos for the same camera (same sensor) FF and in crop mode. Crop mode knocks down the DR for the same sensor by a stop. graph How is that happening? Answer the crop reduces the total light captured and with that SNR goes down.

An analogy: You have two cookie tins one 8x10 inches and the other 11x14 inches. You put them both out in the rain (a very even rain) for the same length of time. They both accumulate water. Measure the depth in the tins of the accumulated water and it's the same for both -- they were exposed the same. Now pour out the water from each tin into two separate beakers. You have two different total amounts of water. More water is more signal and so better SNR.

 

[AlanKlein]

If you switch a camera into crop mode you effectively have a different size sensor. The area of the sensor outside the cropped center is no longer part of the captured image.

SNR is not only a function of sensel size but also of total light captured by the sensor independent of the sensel size. Look at these two DR plots at Photons to Photos for the same camera (same sensor) FF and in crop mode. Crop mode knocks down the DR for the same sensor by a stop. graph How is that happening? Answer the crop reduces the total light captured and with that SNR goes down.

An analogy: You have two cookie tins one 8x10 inches and the other 11x14 inches. You put them both out in the rain (a very even rain) for the same length of time. They both accumulate water. Measure the depth in the tins of the accumulated water and it's the same for both -- they were exposed the same. Now pour out the water from each tin into two separate beakers. You have two different total amounts of water. More water is more signal and so better SNR.

The analogy doesn't make sense to me because the amount of water per square inch is still the same for both tins. So similarly, each pixel element has the same SNR or so it would seem whether you're in crop or FF mode. What are the reasons the SNR changes when you flip between crop and FF modes?

 

[Ysarex]

The analogy doesn't make sense to me because the amount of water per square inch is still the same for both tins. So similarly, each pixel element has the same SNR or so it would seem whether you're in crop or FF mode. What are the reasons the SNR changes when you flip between crop and FF modes?

From my previous post; "SNR is not only a function of sensel size but also of total light captured by the sensor independent of the sensel size."

I shot it for you and you can see the difference. I used a Nikon Z7. I set the camera up in front of some items. Set the exposure in M so no chance of a change. Took the photo in FX mode (image below for reference). Switched to DX mode and zoomed the lens so the framing was identical -- taking the same photo FX and DX. So it's the same physical sensor, exact same exposure with the camera in the same place and just a change in the zoom focal length. ISO 1600 1/6 sec f/8 for both.

It's a subtle difference but the noise variance is obvious in the 100% side by side below.

P.S. There's a slight DOF difference -- DX sensor has a bit more DOF.

 

[AlanKlein]

The resolution is different between FF and DX modes. With DX mode you have less pixels looking at the same subject. You're comparing apples to oranges.

 

[Ysarex]

The resolution is different between FF and DX modes. With DX mode you have less pixels looking at the same subject. You're comparing apples to oranges.

Yes, the resolution is different. Therefore, according to you, everyone who tries to compare the differences between FX and DX is wasting their time in apples to oranges comparisons -- it's just resolution. Posted this earlier: graph -- that's the same sensor producing two different plots for DR (FX and DX). Can you explain why the difference in resolution is causing the DR difference? If it's not resolution what is it?