Do all Digital Camera Think? - DPChallenge Forums

Canon EF-S 17-85mm f/4-5.6 IS USM

04/03/2004 09:05:44 AM · #1

Well a strange title i guess.

Well whole point is that i tend to shoot Photographs for my business using studio strobes. After figuring out what exposure is the best i shoot.

What i have noticed is that when shooting at night, with only modelling lights on when i shoot i get lot of noise at 100 @ f8-9 but same won't hold true when shooting in day with bit of ambient light creaping in.

My point is that though my camera ( powershot a40) is not equipped to shoot with external flash , I shoot using digital peanut slave. So i guess my camera when at 100 IS0( pretty slow speed film) and that too at f8-9 judges the scene with only two 100watts modelling lights( at night time) reacts with lots of noise in sensor without reasling that when actually i click the shutter , there will huge amount of light will be reproduced from two strobes.

I just wanted to know what happens with digital camera that can use external flash. Do they keep in mind the additinal light would be available and thus won't react way a40 does.

One thing strange is that I get fabulous printouts, I mean after i get printouts i find it difficult that these printout are from the digital image that i saw on monitor filled with noise.
P.S please note noise is only when shooting in totally dark room at night with only two modelling lamps on.

Mark

Canon EOS-600D/T3i Rebel

04/03/2004 09:28:26 AM · #2

I'm not sure. my C 750 is pretty good about meetering light before using a flash. If you know aprox. what settings you want, you could do it manually and bypass the meetering all together. It may take a little trial and error, byt when the pics are digital, it doesn't really matter.

Also, What kind of meetering are you using?

lightpro1

Nikon D100

04/03/2004 09:40:18 AM · #3

General,

Your noise problem might be from under-exposure. Try adjusting the exposure compensation on ytour camera to over-expose by 2/3 to 1 full stop. I have the same problem in an old ice rink that I photograph hockey games in. When I started adjusting my exposure compensation, the noise problem was greatly improved.

04/03/2004 10:58:06 AM · #4

Some digital cameras do take into account external lights. My Minolta A1, and others, have a PC Sync socket to connect to, and control, external studio lights. But for your camera to include ambient light, or lack thereof, in it's calculations you need more sophisticated equipment. Shooting all your shots after dark is the easiest way to control that element of your lighting.

04/03/2004 11:27:37 AM · #5

Originally posted by Quickshutter:

I just do metering out of sheer past experince, since i work in same room, so i know that i need to expose @ 100 IS0 @ f8-10.

Distance bewteen lights and subject is same

04/03/2004 11:39:46 AM · #6

Originally posted by lightpro1:

I am sure you are right. But i wanted to know are there any digital camera that don't react for given light situtation. What i mean is lets suppose i need to expose a scene at f-8 , film speed is 100. Camera simply accepts my setting , with a assurance that i am using external flash and it's ccd doesnt have this activity that this scene has less light( it will be lit by 2 100w bulbs).

I mean if you take your camera in dark you can see noise level start increasing ( despite the fact that i have set correct setiing, you can increased noise level on display, or it just lcd display noise level and not the sensor noise level

Message edited by author 2004-04-03 11:40:56.

joshua

Canon EOS-500D Rebel T1i

Canon EF 50mm f/1.8 II

04/03/2004 11:42:01 AM · #7

mine stopped thinking so i had to send it in for a psych eval

lightpro1

Nikon D100

04/03/2004 11:53:38 AM · #8

The fact that you are getting good prints out of the images might indicate that this is a characteristic or limitation of your camera itself. I'm not familiar with the Canon A40 enough to tell you that this is the case. I know that with the Canon 10D or the Nikon D100, this is not an issue. If you have noise on the LCD, then you have noise in the finished image. I would still try to over expose to see if that improves the finished print image, though. Try bracketing the next time you photograph with this method (shoot 1 at normeal exposure, 1 at 1/3 over, 1 at 2/3 over and 1 at 1 stop over). Make sure that you keep notes of which exposure is which setting and make the decision based on this as to how you proceed in the future.

04/03/2004 12:33:39 PM · #9

i will follow what u mentioned

04/03/2004 01:02:25 PM · #10

What exposure mode are you shooting in? If you are using a Manual mode I think your camera does not consider the possibility of flash, whether it is external or internal, and just goes with your settings. Are you using studio strobes that only fire during exposure, or are you using regular studio lighting which is on during your camera's metering?

04/03/2004 01:39:06 PM · #11

I am using manual mode, well it does consider about internal flash , reason is that if i switch of internal flash, lcd becomes really dark untll shutter speed is decreased to something like 1/5 sec .

Well in manual mode in my camera there is no metering , it is just like shooting with a manual slr with a flash on, i mean like in manual slr ( which i have used) , when i wanted to shoot using flash i would simply set aperture , set shutter shutter speed for x ( shutter sync speed) , place flash on hot show and click.

Similarly in my camera what i do is I choose manual mode, set aperture to f-8(lets say that what i need) and simply fire , i choose shutter speed of 1/125 sec( i really experimented alot and realised after i swictch on the flash, it doesnt matter what shutter spped i choose result are same i.e 1/125 sec is same as 1/15 sec).
Now i simply click, Well as far as my strobes are concerened , modelling lamp of 100w is on.
There is metering being done it si all manual. I mean canon expected us to be super genius that in manual mode they didnot provide any metering, leaving shutter speed and aperture( dependant on zoom setting), i mean i dont know how did they expect to set both without a meter.

any ways here are some photographs which i took with above mentioned set up and a had good result Good Sample
Here are two test sample i shoto today.

First one shot at 100 iso f-8 , second one shot is0 50, f3.2, my point is dont you think there is yellow cast in second one, i mean i thought there would be washout of color ( background is pretty washout) but why yellow ness or is it that my monitor is showing wrong
First Pic
Second Pic
Noise is visible in First Pic

Message edited by author 2004-04-03 13:46:50.

Canon EF 17-40mm f/4L USM

04/03/2004 02:43:12 PM · #12

I may be completely wrong but to my untrained eye what you are calling a yellowish cast in the second pic is a variation in the White Balance. Could be caused by a change in ambient light or by a change in your camera's WB setting, but I would be surprised if it were from different ISO and aperture settings alone. That's just my opinion. Wish I could be more helpful but I don't know much about studio shooting. Maybe a close look at EXIF info will show some other variation besides ISO and aperture.

peecee

Canon EOS-5D

04/03/2004 03:17:57 PM · #13

I am far from an expert but what Harvey says looks like the case, I assume the backdrop is white, in which case it obviously isn't in the 2nd picture.I have met the same problem several times and reset the white balance resulting in a much better photograph.

04/03/2004 10:09:15 PM · #14

I had set wb to auto for both, photograph were taken within seconds of each other and noting else.
Back drop is white plastic sheet i picked yesterday after noon

04/04/2004 12:30:19 AM · #15

Just as a comparison, try taking two shots with the same settings as your First Pic and Second Pic but with the WB set to another setting other than Auto, maybe try tungsten for the 100W.