Is there somethign wrong with my camera?

[shorty6049]

Hey everyone... I own a sony alpha and i've always felt like there might be somethign wrong with it... I've seen concert phtos taken by a fellow with a canon 20d (i think) and he said he was shooting at around iso800-1600 at f4 with a shutter speed of about 1/160". I was shooting at f5.6 and at mostly 1600 iso, with a shutter speed closer to 1/30" our pictures came out very similarily exposed but his needed a much shorter shutter speed. and i always sort of feel like not enough light is getting to the sensor or something....
here's an example. the first photo illustrates closely what the actual light in the room looks like. the second photo was taken in the same conditions at ISO 100, and f1.7, shutter speed 1/160" should this image be brighter than it is? I just want to know if its worth sending into sony or not. thanks!

 

[elsaspet]

Where are you metering from?

 

[Big Mike]

Can you list the exposure settings for both shots?

The difference from F4 to F5.6 is one stop (it's not a linear scale). One stop is half as much or twice as much light. So one stop less light than 1/30, is 1/60, one more stop less is 1/120 (1/125).

 

[shorty6049]

the first photo was taken at i think a shutter speed of around 1/30" , the second was at 1/160. Aperture was 1.7 for both, and ISO was 100 for both


also, does it matter where i'm metering from? doesnt the brightness pretty much just depend on shutter speed/ISO/aperture? i thought the metering just told me how to set the shutter speed.... i was metering probably on the phone though. i just feel like i should be getting more light than i am. I was shooting at 200mm and f5.6 at ISO 1600 as well as 20mm f1.8 at ISO 1600 and i usually used the same shutter speed for both those situations. But the meter told me to do that, and the meter was right about the calculations. I messed up sensor wouldnt effect the metering though, would it?

 

[Garbz]

The light image: 1/20th f1.7, iso100

The dark image: 1/160th f1.7, iso100

That means there is a 3 stop difference in light between the images. If the second image were recorded at iso800 it should be as bright as the first one. Or if the first was set at f6.3??? it should be as dark as the second. It is all working. I suggest you read up on aperture, shutter, and iso on wikipedia. They have excellent info on how it is all related.

 

[shorty6049]

well i mean, i know how they're related mostly, but i just feel like a lot of times i'll look at a photo and it'll have the info on the bottom and i'll think to myself. man, if i used those settings, it would be way underexposed.... maybe i just need to kick up the iso... at the concert though i was forced to shoot at around 1/30" just to get proper exposure while someone with a lens with only a 1 stop advantage over mine was shooting at 1/160" at the same ISO