how to compare camera to mobile phone?

Started 1 month ago | Discussions thread
Gerry Winterbourne Forum Pro • Posts: 15,652
Re: Same settings.....
1

SergeyAU wrote:

PhotoTeach2 wrote:

tedolf wrote:

SergeyAU wrote:

Please see my pictures where I compare the similarly lit pictures. But I had to use different settings on my camera to achieve similar results. Had to go to a full second and twice the ISO

https://www.dpreview.com/forums/post/62675981

As I said before, exposure is independent of sensor size. The differences you are seeing are due to the cell phone internal post processing. You can do the same things with a photo taken with your camera at the same exposure settings in post processing.

Tedolph

But Teddy ... there really was not (much) difference. His camera f/stop was 2-stops slower so he had to use longer SS and higher ISO.

How did you work out 2-stops? Mobile was f/1.5 and camera was f/3.5. Do you take higher full stop number (f/2 for f/1.5 and f/4 for f/3.5) and subtract? Same for shutter speed - 1/4" -> 1" are 2 stops as well?

In photography a "stop" means a doubling or halving of the light. For shutter speed it's easy - half the exposure time (1/100s v 1/50s) is one stop darker; four times the exposure time (1s v 1/4s)  is 2 stops = 2 x 2 - brighter.

Aperture is trickier at first sight because a wider aperture increases its area by the square of the increase. Rounding the numbers, an increase of 1.4X makes one stop difference (because 1.4 x 1.4 =2 to the nearest rounding). So 1.5 x 1.4 = 2.1 is one stop; 2.1 x 1.4 = 3 (rounded) is a second stop. So f/1.5 to f/3.5 is a fraction over two stops.

The result was less than 1-stop discrepancy, which can easily be within margin-of-error considering it was indeed a phone w/ probably less-accurate USO calibration, (compared to "real" camera where ISO calibration would be more accurate).

And here you mention "less than 1-stop discrepancy". You mean that 2 images LOOK similar to each other to disregard the differences due to ISO calibration?

No. He means that when you do the maths between the two sets of settings the results are within one stop of each other.

If they look similar despite this difference it's because the two cameras process their data differently. And that difference in processing is why it's a mistake to use the phone to learn camera settings.

Just making sure that I understand

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Gerry
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First camera 1953, first Pentax 1985, first DSLR 2006
http://www.pbase.com/gerrywinterbourne
gerry.winterbourne@ntlworld.com

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