ISO, D40, ME or the camera?

puyjapin · Mar 3, 2009

ok i will admit i dont fully understand ISO and i stil shoot jpeg!
I will be honest when i change the ISO i notice little or no difference in the exposure. I comprehend aperture , shutter etc but the same shot on various iso's seem to make little or no difference..why is this?
Also i notice when i set my io to say 200, on the exif data on my camera the iso reads 1600, in red text? I can assume that he shot is 200 becaus there is no noise so why does the readout say a another iso to that i have set?

LarryD · Mar 3, 2009

Nothing wrong with shooting jpeg.............lots of people do.

ISO, indeed, is only a small change.. For each doubling of ISO (sensor light sensitivity), you only gain a single f-stop. So, in theory, going from ISO 100 to ISO 200 may only translate into going from an f-stop of 2.8 to one of perhaps 3.5.

But, what it also might do is give you a speed from 1/15 of a second up to a more manageable 1/30...............

In low light, don't just automatically crank up to the highest ISO on the camera, because you will get noise (you don't get something for nothing); understand what settings are available for each ISO setting and then use the one that will still get the shot with the least amount of degradation...

Can't answer your specific camera question although I suspect auto ISO.

NateS · Mar 3, 2009

Your auto ISO is set to on. THis is why you don't see a change. If you are shooting in low light with auto iso on and iso set at 200, it is raising it to 1600iso because of the low light. If you then set the iso to 400 or 800 in the same scene/place, auto iso is still increasing it to iso1600 so you're getting the same exact shot. If you want full control of your iso then turn auto iso off. When the ISO is lit up in red after shooting that means that auto iso was used instead of the iso you had set.

Post an example of this shot that shows ISO 1600 in red in the exif. You say there's no noise, but your standards of noise may be different than mine. I'd love to see a shot at ISO 1600 on a D40 that has no noise. I know the D40 is fairly good with higher iso's but I find it hard to believe there is no noise at that iso.

puyjapin · Mar 3, 2009

how is thisdone then as im choosing iso 200, not auto and im in manual mode on the camera

MikeBcos · Mar 3, 2009

puyjapin said:
how is thisdone then as im choosing iso 200, not auto and im in manual mode on the camera

Rob, in ISO auto the camera overrides your setting, page 76 of the manual explains it very well.

puyjapin · Mar 3, 2009

its not in iso auto im choosing 200 etc

NateS · Mar 3, 2009

puyjapin said:
how is thisdone then as im choosing iso 200, not auto and im in manual mode on the camera

You have to disable auto ISO in the menu. It doesn't matter if you are shooting full manual, if auto ISO is on it will adjust it to meet the exposure needs regardless of what you set ISO at. Go into your menu and disable it and you'll be set.

puyjapin · Mar 3, 2009

sorry chaps, ive found what ur on about...so seems ive had the camera 4 months and it was auto boosting the iso..perhaps id of got better shots on a slower shuter with cntro on the iso

MikeBcos · Mar 3, 2009

puyjapin said:
its not in iso auto im choosing 200 etc

ISO auto is selected using option 10 on the Custom Setting menu, that is independent of the ISO settings available in the Shooting menu.

puyjapin · Mar 3, 2009

no wonder i could never see the difference it was always being overridden....any other settings i might have missed...let me know pls!!!!

MikeBcos · Mar 3, 2009

I actually find auto ISO very useful, I have it on with a maximum sensitivity of 800 since that gives a quality I feel is acceptable. If I want higher than that I can select it myself.

The D40 has a lot of options buried and hidden in the menus, I just sit and mess with mine going through them all seeing what is hidden in there. I also flick through the manual a lot, I'm hoping one day to learn all the options available.

manaheim · Mar 3, 2009

MikeBcos said:
ISO auto is selected using option 10 on the Custom Setting menu, that is independent of the ISO settings available in the Shooting menu.

And people wonder why some say the D40 is unsuitable...

dEARlEADER · Mar 3, 2009

manaheim said:
And people wonder why some say the D40 is unsuitable...

unsuitable for what??

it's perfectly suitable and capable for the task it was designed for.. especially considering it's age... it the right hands the D40 rocks...

remember as well, even though the D300 has a fixed ISO button one must still enter the menus to disable the auto-iso...

manaheim · Mar 3, 2009

^^^ having a menu option that over-rides a setting is really confusing, even for someone new to photography. Given that it's "designed" as a camera for people trying to get into the field, that makes it unsuitable.

Well... to be fair, that kind of underscores it's unsuitability.

That alone doesn't make it unsuitable.

MikeBcos · Mar 3, 2009

manaheim said:
^^^ having a menu option that over-rides a setting is really confusing, even for someone new to photography. Given that it's "designed" as a camera for people trying to get into the field, that makes it unsuitable.

Well... to be fair, that kind of underscores it's unsuitability. That alone doesn't make it unsuitable.

The default setting for the auto ISO option is off, most people won't find it until they are more familiar with the camera and photography.

I find my D40 to be very suitable.