Manual vs. Aperture Priority mode

[ralphh]

But then you have to adjust your ISO every time you change apeture unless it's bright enough that you're always ok at base ISO. That just gets annoying. And if you get caught up in the moment and forget the ISO part you either get motion blur, or more noise than you need to.

I'm struggling at times to remember this with the 5dmk2 I got for xmas (from myself); the auto ISO is next to worthless for people photography with a 35mm lens (which just happens to be my most used lens and most common subject) - 1/30th is just not fast enough for shooting people, and even worse with kids.

It's been at least 4 years since I had a camera without decent auto iso, so I'm completely out of the habbit of remembering to constantly change it and it's soo frustrating remembering to do something that I was happy not to have to do for so long.

Unlearning 4 years worth of habbit is hard, and I've ruined a lot of otherwise good shots because of it :banghead:

I'm actually considdering shooting Manual mode full time, just to force myself to actually look at the shutter speed as well as the apeture :crazy:

 

[EIngerson]

But then you have to adjust your ISO every time you change apeture unless it's bright enough that you're always ok at base ISO. That just gets annoying. And if you get caught up in the moment and forget the ISO part you either get motion blur, or more noise than you need to.

I'm struggling at times to remember this with the 5dmk2 I got for xmas (from myself); the auto ISO is next to worthless for people photography with a 35mm lens (which just happens to be my most used lens and most common subject) - 1/30th is just not fast enough for shooting people, and even worse with kids.

It's been at least 4 years since I had a camera without decent auto iso, so I'm completely out of the habbit of remembering to constantly change it and it's soo frustrating remembering to do something that I was happy not to have to do for so long.

Unlearning 4 years worth of habbit is hard, and I've ruined a lot of otherwise good shots because of it :banghead:

You absolutely DO NOT have to change your ISO every time you change the Aperture. You have to change the ISO when the conditions change. If you set your ISO to 200 on a nice sunny day and change your Aperture, the camera will change the shutter speed to expose in the middle. Likewise with indoors using 800 and so on. You set the ISO to an acceptable setting to achieve the the aperture you want and still have the shutter speed to get acceptable sharpness.

 

[ralphh]

Of course you do - changing the apeture is changing the conditions at the sensor - close the apeture 1 stop and the world gets twice as dark as far as the sensor is concerned!!

If you're at ISO 800 indoors, and go from f4 to f2.8, then you can drop your ISO to 400 - and should do for better noise - if you were happy with the shutter speed.

Similarly, if you were at f2.8 1/60 ISO 400, and went to F4, you'd need to go up to ISO 800 to maintain 1/60 - otherwise the camera will drop it to 1/30 and you'll get motion blur (depending on subject).

The only time you don't need to worry about ISO is when it's very bright and going from say f2.8 1/1000 ISO 100 to f4 1/500 ISO 100 makes no difference to you as both shutter speeds are fast enough and ISO is already at base.

 

[EIngerson]

Of course you do - changing the apeture is changing the conditions at the sensor - close the apeture 1 stop and guess what - the world just got twice as dark as far as the sensor is concerned!!

If you're at ISO 800 indoors, and go from F4 to f2.8, then you can drop your ISO to 400 - and should do for better noise.

Similarly, if you were at f2.8 1/60 ISO 400, and went to F4, you'd need to up to ISO 800 to maintain 1/60 - otherwise the camera will drop it to 1/30 and you'll get motion blur (depending on subject).

The only time you don't need to worry about ISO is when it's very bright and going from say f2.8 1/1000 ISO 100 to f4 1/500 ISO 100 makes no difference to you as both shutter speeds are fast enough and ISO is already at base.

Wrong, you don't worry about shutter speed. the camera does. If you set the ISO at 400 and change from F2.8 to F8 your shutter speed is going to slow down. That's it. The point you brought up was the same thing I said, you changed your environment. For example, if you go from outside to indoors you will change your ISO. If you stay out doors and take a photo of your kid at F2.8 and then change aperture to F8 and snap one you'll only change the depth of field. The camera will automatically change the shutter speed to give you the exact same exposure.

 

[ralphh]

In that case I think my camera must be faulty - things seem to get all blury at slow shutter speeds for me. Obviosuly that doesn't happen for you :raisedbrow:

Seriously? You can freezy in motion a child running about with your shutter speed at 1/10th second?

Cause 1/10th is what your camera will pick if you go from f2.8 @ 1/80th to f8 without changing ISO.


Unless you're taking about shooting landscapes from a tripod you DO need to worry about shutter speed, regarless of whether it's you or your camera changing it.

 

[EIngerson]

Seriously? You can freezy in motion a child running about at 1/10th second shutter speed?

1/10th is what your camera will pick if you go from f2.8 @ 1/80th to f8 without changing ISO.


Unless you're taking about shooting landscapes from a tripod you DO need to worry about shutter speed, regarless of whether it's you or your camera changing it.

What are you talking about? Where do you come up with 1/10th?

Note, before we go any further, This is just an internet debate and please don't read my type as "bullyish" or anything of the sort.

 

[ralphh]

There are a lot of threads and websites that explain how exposure works....

 

[EIngerson]

There are a lot of threads and websites that explain how exposure works....

LOL, You should read them. What you just posted is for whatever light you are currently standing in. (your environment) That means you have to change your ISO. Once you have an ISO that gives you acceptable shutter speeds for the "environment" you are in, you don't have to change it again until you leave that environment.


Anyway, I'm over it. If you want the camera to pick it for you just use the green box.

 

[ralphh]

Ok, so lets assume you have your camera set at ISO100


If you pick f2.8, you camera will for example pick 1/80th of a second shutter speed so that the scene is properly exposed. And 1/80th is fine and dandy for most things with normal lenses and and "normal" subjects.

If you close down to f4, that's half as much light coming in through the apeture, and it will pick 1/40th to properly expose
If you close down to f5.6, that's half as much light again coming in through the apeture, and it will pick 1/20th to properly expose
If you close down to f8, that's half as much light again coming in through the apeture, and it will pick 1/10th to properly expose

By the time yuo get to this point, unless your camera is on a tripod and your subject is static, you're just going to be photographing blur.

Raising your ISO to 200 doubles the sensitivity and the camera will up the shutter speed back to 1/20th
Raising your ISO to 400 doubles the sensitivity again and the camera will up the shutter speed back to 1/40th
Raising your ISO to 800 doubles the sensitivity again and the camera will up the shutter speed back to 1/80th

back where we stared.

So to go from f2.8 to f8 with a constant shutter speed, you need to go from ISO 100 to iso 800

Which is annoying, as all I wanted to do is go from f2.8 to f8, not do that then took at me shutter speed, see it's in the toilet, hold down the iso button and crank it up until it's exceptable, then take my shot. Back before Auto ISO get invented, this seemed fine and reasonable. Now years later, going to a camera that doesn't have it is just "AAAGH"!

 

[runnah]

There are a lot of threads and websites that explain how exposure works....

LOL, You should read them. What you just posted is for whatever light you are currently standing in. (your environment) That means you have to change your ISO. Once you have an ISO that gives you acceptable shutter speeds for the "environment" you are in, you don't have to change it again until you leave that environment.

This...

I mentally pick out what ISO I am going to use for the situation I am in. I rarely change it unless I go into a different room or someone turns on a light. One I have that picked out I will change the f-stop and shutter speed a bunch.

Sounds like you are making extra work for yourself. (this is to Ralphhy)

 

[ralphh]

So I should just pick an ISO and ignore the fact that when i change apeture I might get unacceptably low shutter speeds / pick a really high one and get more noise than I needed to when I open up the apeture?

Sounds like a pretty sloppy way of taking photos.

 

[EIngerson]

Okay, if I'm at ISO 100 @ F2.8 and my camera picks 1/80th I'm not going to stay at ISO 100. That's why I said "for the conditions". If I'm outside shooting motocross on a sunny day I'll leave my ISO at 200 all day, AND change aperture all day to get the depth of field I want. I'll never touch my ISO unless the clouds roll in and totally grey it out.

Likewise if I'm in my house messing around during the day. I'll stick ISO 800 (or whatever ISO get's the shutter speed I want at the time) and never change it unless I change the environment (i.e add a flash) I don't change the ISO unless my shutter speed becomes unacceptable.

I also do not change the ISO EVERY TIME I change my aperture. And I definitely will not let my camera pick it for me.

 

[ralphh]

And I definitely will not let my camera pick it for me.

Well maybe you should - then it would be at a more appropriate value

There's no advantage to shooting at ISO 800 @ 1/400th when you could be shooting ISO 200 @ 1/100

Just makes no sense to me - why have more noise than you need to? Why not optimise your ISO?

I know what shutter speeds I need to photo people that are more or less static - it's about 1/60th, so I want to be as close to that as possible, not suddenly be at 1/500 because I went from f4 to f1.4. I still want to be at 1/60th and drop my ISO cause being at 1/500 does nothing for me, as where dropping my ISO does.



Also, if you don't change it when you change apeture, there's not much point changing it when the light changes either - it's all the same thing in the end

 

[runnah]

That's why I said "for the conditions".

Yes, and even then it's about knowing what you want the end result to look like. I recently shot some photos at ISO 200 f-11 with a 3 minute exposure. Why? Well I wanted a night shot of a thicket, that wasn't super grainy and very sharp. Sure I could have gotten the exposure time down to 30 seconds with using a high ISO and a large f-stop, but I know what I wanted and adjusted the setting accordingly.

 

[runnah]

There's no advantage to shooting at ISO 800 @ 1/400th when you could be shooting ISO 200 @ 1/100

I can think of a 100.