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ISO / Sensitivity accuracy

In a new addition to our reviews we are now measuring the actual sensitivity of each indicated ISO sensitivity. This is achieved using the same shots as are used to measure ISO noise levels, we simply compare the exposure for each shot to the metered light level (using Sekonic L-358), middle gray matched. We estimate the accuracy of these results to be +/- 1/6 EV.

Both the Sony DSC-R1 and Olympus E-500 used exposures which matched our metered light level (returning middle gray on our GretagMacBeth ColorChecker), as we have noted previously the Canon EOS 350D (Digital Rebel XT) proved to be about a third of a stop more sensitive than indicated.

Indicated
sensitivity
Sony DSC-R1
(actual sensitivity)
Canon EOS 20D
(actual sensitivity)
Olympus E-500
(actual sensitivity)
ISO 100 n/a ISO 125 ISO 100
ISO 160 ISO 160 n/a ISO 160
ISO 200 ISO 200 ISO 250 ISO 200
ISO 400 ISO 400 ISO 500 ISO 400
ISO 800 ISO 800 ISO 1000 ISO 800
ISO 1600 ISO 1600 ISO 2000 ISO 1600
ISO 3200 ISO 3200 n/a n/a

ISO Sensitivity / Noise levels

ISO equivalence on a digital camera is the ability to increase the sensitivity of the sensor. The works by turning up the "volume" (gain) on the sensor's signal amplifiers (remember the sensor is an analogue device). By amplifying the signal you also amplify the noise which becomes more visible at higher ISO's. Many modern cameras also employ noise reduction and / or sharpness reduction at higher sensitivities.

To measure noise levels we take a sequence of images of a GretagMacBeth ColorChecker chart (controlled artificial daylight lighting). The exposure is matched to the ISO (ie. ISO 200, 1/200 sec for consistency of exposure between cameras). The image sequence is run through our own proprietary noise measurement tool (version 1.4 in this review). Click here for more information. (Note that noise values indicated on the graphs here can not be compared to those in other reviews). Room temperature is approximately 22°C (~72°F), simulated daylight lighting.

Sony DSC-R1 vs. Canon EOS 350D (Digital Rebel XT) vs Olympus E-500

Note that we have chosen to compare to the EOS 350D for these tests because price-wise (including a similar lens) it's closer to the DSC-R1 than the EOS 20D. Also the noise profile of the EOS 350D and EOS 20D are as good as identical.

  • Sony DSC-R1: Aperture Priority, Manual WB,
    Default Parameters, JPEG Large / Fine
     
  • Canon EOS 350D: Canon 50 mm F1.4 lens, Aperture Priority (F4), Manual WB,
    Parameters 1 (default), 50 mm F1.4, JPEG Large / Fine
     
  • Olympus E-500: Olympus 50 mm F2.0 Macro lens, Aperture Priority (F3.5), Manual WB,
    Default Parameters, JPEG Large / Fine, ISO Boost: On
Sony DSC-R1
ISO 160
Canon EOS 350D
ISO 100
(125 equiv.)
Olympus E-500
ISO 100
Sony DSC-R1
ISO 200
Canon EOS 350D
ISO 200
(250 equiv.)
Olympus E-500
ISO 200
Sony DSC-R1
ISO 400
Canon EOS 350D
ISO 400
(500 equiv.)
Olympus E-500
ISO 400
Sony DSC-R1
ISO 800
Canon EOS 350D
ISO 800
(1000 equiv.)
Olympus E-500
ISO 800
Sony DSC-R1
ISO 1600
Canon EOS 350D
ISO 1600
(2000 equiv.)
Olympus E-500
ISO 1600
Sony DSC-R1
ISO 3200
Canon EOS 350D
n/a
Olympus E-500
n/a

The DSC-R1's noise reduction strategy appears to be no noise reduction from ISO 100 to 400, then at ISO 800 noise reduction begins and there is a decrease in sharpening, at ISO 1600 the noise levels become too much for the noise reduction to contain. It's interesting to observe the difference between the DSC-R1 and Olympus E-500 at ISO 1600, the Olympus image appearing much softer due to noticeably heavier noise reduction.

The DSC-R1's higher ISO noise is characterized mostly as chroma blotches, most notably from the red channel which cause cyan colored patches in gray areas and red patches in shadows. Areas with a lower 'signal' (shadows) will suffer more. Compared to the two other cameras here the DSC-R1 performs well up to ISO 800 (with some softening), at ISO 1600 and 3200 images are still usable but there's a clear increase in blotchy noise which is especially noticeable in shadow areas (seen on our black patches above).

Luminance noise graph

Our new luminance noise graph shows noise levels in both the middle gray and black patches. As you can see the R1's primary noise 'problem' is in shadows (the dotted lines), you can also see the effect of noise reduction / sharpening reduction at ISO 800 with a flattening of the gray noise line.

Indicated ISO sensitivity is on the horizontal axis of this graph, standard deviation of luminosity (normalized image) on the vertical axis.

Chroma (color) noise graph

In addition to measuring luminance noise we now also measure chroma (color) noise. Note the sudden drop at ISO 800, this is the noise reduction system taking effect, then at ISO 1600 noise levels are back up again. Overall not a bad performance, about the same as the other two cameras

Indicated ISO sensitivity is on the horizontal axis of this graph, standard deviation of each of the red, green and blue channels (normalized image) are on the vertical axis.

Effect of heat build-up from live view (over time) on noise

One thing we were concerned about was the build-up of heat in the sensor due to the live view. To test this we took a sequence of noise tests at two minute intervals. Between sequences the live view was constantly maintained. Below ISO 1600 there is almost no difference, at ISO 1600 we saw a small spike near the end of the test. At ISO 3200 we can see a very slight increase in noise but this fell away at the end of the test (camera modifying noise reduction level to compensate for sensor temperature?).

Indicated ISO sensitivity is on the horizontal axis of this graph, standard deviation of each of the red, green and blue channels (normalized image) are on the vertical axis.

Black patch / Shadow noise

As noted above the DSC-R1's noise is primarily characterized by color blotches in shadows (simulated by the black patch on our test chart). Here we're comparing the breakdown of noise in shadow areas by color channel. The crops below show the full color crop from our black patch and directly below this the contents of Red, Green and Blue color channels. As you can see noise from the red and blue channels produce the mottled patchy appearance of noise in shadows, green will always perform better because there are twice as many green photosites and sensors tend to be more sensitive to it. For this comparison we chose to use the Canon EOS 20D (which has essentially identical response to the EOS 350D but supports sensitivity up to ISO 3200).

Sony DSC-R1
ISO 1600
Canon EOS 20D
ISO 1600
(2000 equiv.)
Olympus E-500
ISO 1600
Sony DSC-R1
ISO 3200
Canon EOS 20D
ISO 3200 (4000 equiv.)
Olympus E-500
n/a
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Comments

Total comments: 6
sukritsaha

Where to get Sony original np fm 50 battery for dsc r1, in india.

Thank you all for your attention.

SUKRIT

0 upvotes
Sdaniella

Sony Cyber-shot DSC-R1: 14.3-71.5mm f/2.8-4.8
Zeiss 73.8∠5.11 ∅ 2.8 ev (Wide)
Zeiss 17.1∠14.9 ∅ 4.8 ev (Tele)

Comment edited 2 minutes after posting
0 upvotes
biffy7

We use this daily (2014). It is slow, but with 2 x 285HV (Original), for product shots. It does a very good job. The color is slightly off. It sits upon a Tiltall tripod from about 25yrs ago. (spotting a trend here). I figure that if I have the equipment sitting around, might as well put it to use.

0 upvotes
Joe186

Who’s “we”? Do you have a mouse in your camera bag?

1 upvote
Pascal Parvex

Had this camera before I bought my first DSLR, the 5D Classic. It is a capable camera, the first time I bought a Sony, as Canon did not have something comparable. I shot two Tokio Hotel concerts with this one, some pictures with 3200 ISO that turned out usable. Just the red tones are a little bit too speckled. Bought a DSLR afterwards because the R1 is quite slow.

0 upvotes
guyfawkes

Agreed about the speed of handling, and by today's standards, the higher ISO settings are quite poor.

But where these aspects don't really matter, its IQ from the superb Zeiss lens can still give a modern dlsr a run for its money. And it would have to be a top of the range one as well, with top jolly optics.

2 upvotes
Total comments: 6