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MatH
09-18-2005, 08:12 AM
I've been doing some tests out of curriosity and compared shots from DS with Canon A510. It seems that with the same ISO and aperture/shutter settings (manual mode) A510 makes brighter images.
Why is that? One of the reasons I bought dSLR is it's higher sensitivity and better low light performance, but it seems that low light performance istn't that mush better at all :confused:

The attached samples were taken at ISO 200 Tv30 Av6.3
As you will see the one from Pentax is considerably darker :(

Ishkabibble
09-18-2005, 10:00 AM
Without full information on the conditions, it is not possible to accurately judge which image is correct. Underexposure would cause a dark image, and would not be a fault of the camera. Therefore, it is not immediately apparent whether the DS is dark due to underexposure, the A510 light due to overexposure, or if another issue such as factory defaults for sensor gain contributed to your brightness observation.

The image from the DS is undeniably darker, but if you look at total image quality, you will note that it contains a more accurate rendition of the original scene.

The image from the A510 contains exceptional noise in the shadow areas; a color cast is also apparent. Prints with these issues will be of marginal quality, even with post processing.

If you print with an Epson, you might try using PIM II to import both images into Photoshop; the increased detail in the DS image will become apparent and your brightness issue will probably be resolved. This will demonstrate what is actually being captured by the cameras.

If you do not use an Epson, or you prefer RAW like I do, try Rawshooter Essentials (it's free) and you'll be able to judge the image from the DS more accurately. Since you are looking at low-light performance, try pulling detail out in low-light areas. It's as simple as two slider bars in the software.

If you simply want a better low-light image without any out of camera alteration, use the in camera processing to boost the brightness. I suspect you'll get similar brightness without the excessive noise and artifacts present in the A510 image.

Spot focus
09-18-2005, 08:24 PM
I've been doing some tests out of curriosity and compared shots from DS with Canon A510. It seems that with the same ISO and aperture/shutter settings (manual mode) A510 makes brighter images.
Why is that? One of the reasons I bought dSLR is it's higher sensitivity and better low light performance, but it seems that low light performance istn't that mush better at all :confused:

The attached samples were taken at ISO 200 Tv30 Av6.3
As you will see the one from Pentax is considerably darker :(

Hi MatH What AE setting were you using or were these shot taken on manual? also what was the white balance setting?I took some 3 shots of a wall light using the 3 AE settings there was a huge differance

MrSleep
09-19-2005, 12:41 AM
I've been doing some tests out of curriosity and compared shots from DS with Canon A510. It seems that with the same ISO and aperture/shutter settings (manual mode) A510 makes brighter images.
Why is that? One of the reasons I bought dSLR is it's higher sensitivity and better low light performance, but it seems that low light performance istn't that mush better at all :confused:

The attached samples were taken at ISO 200 Tv30 Av6.3
As you will see the one from Pentax is considerably darker :(


Math!!!

Canon A510's ISO rating is understated!

A510 ISO:50 = ISO:100 in real world camera calibration.

I have read about this from the feedback to the review of Canon A80 Powershot at Photo.Net.

Here is an excerpt by Bob Atkins.

"I wonder why Canon would not use the fact that their ISO rating is off to make it into a marketing point? I mean, a camera with an ISO rating with 100-800 sounds more impressive to an average consumer than one with a 50-400 rating (even though we know better)."

Drop the Canon to ISO:100 and keep the Pentax at ISO:200 then see how it compares.

MatH
09-19-2005, 01:13 AM
For those of you wandering under what conditions were these images taken:
I took them side by side with the same manual settings on both cameras. On both cameras ISO was at 200, aperture at 6.3 and shutter time at 30.

I'm well aware that dSLR like *Ist DS makes superior images compared to P&S like A510 that can be post processed if shooting in raw (and I shoot only in raw), but I was suprissed to see huge difference in image brightness taken with identical manual settings at identical lihgt conditions.

I also noticed that for cameras to work aproximately the same DS has to have iso twice as high as A510 so the answer from MrSleep seems logical.

tadah
09-19-2005, 05:47 PM
but the ds there is a much better image - look at all the noise from the p&s! that's not good low-light photography.

astro
09-19-2005, 07:30 PM
Maybe the ist DS uses ISO200, but turns down the brightness in half so you get the noise levels of ISO100? That probably explains why the ist DS has twice the ISO levels of competitors, 200-3200 vs 100-1600.

MatH
09-20-2005, 01:30 AM
Maybe the ist DS uses ISO200, but turns down the brightness in half so you get the noise levels of ISO100? That probably explains why the ist DS has twice the ISO levels of competitors, 200-3200 vs 100-1600.
I don't think so. All Nikons in it's grade start at ISO 200 and end at 1600. I'll do some comparison tests with Canon EOS 300D (Dig. Rebel) when I get to meet with my friend.