Using Manual Mode vs Av mode

darich · Nov 10, 2005

I recently bought a book about exposure in photographs. In the book, which contains some stunning and well exposed shots, the photographer said that he uses "M" mode all the time. He sets the aperture manually, then adjusts the shutter speed until the camera tells him the exposure is right.
I totally understand how that works and the relationship between aperture and exposure.
However, am i missing something by not understanding the difference between his method and Av?
When using Av doesn't the camera adjust the shutter speed automatically to suit the manually chosen aperture? If so, then it's quicker than using "M" mode.
My understanding is the same with Tv mode except in this mode, the photographer manually sets the exposure and the camera adjusts the aperture automatically.
Can anyone explain to me why he, or any photographer, would use "M" mode when not looking to alter the exposure of an image?

thebeginning · Nov 10, 2005

i only use M if I want to do creative expsosing. otherwise i use Av. It's basically so that you can read the meter, then choose how you want to expose the scene. When in Av, you may meter it how you want, but when you compose it it reads something else, losing the previous meter reading. in M mode you can just meter the scene until you get it how you want, then compose, and you wont have to worry about your setting changing.

darich · Nov 10, 2005

So the "M" mode is really only if you want to manually adjust the exposure to deliberately over or underexpose an image?
I guess it could be used for bracketing by quickly changing the exposure between shots?

hobbes28 · Nov 10, 2005

Not always. I shoot in Manual mode all of the time for a few reasons. One reason is that it keeps me on my toes and shooting like I learned..without any meters or automatic frills. The other reason is that you can control your contrast and DOF in different settings more with the manual mode (at least the one on the D70) because Av seems to put Lo or Hi up a lot when Manually, it can be adjusted even further. eg. Full sunlight f1.8 and a shutter speed of 1/8000 which in Av mode at 1.8 would say Hi...and over expose while trying to shoot at 1/4000.

thebeginning · Nov 10, 2005

well yes, but you can use it to make sure the camera doesnt change exposure also. like if you want to expose for a particular part of a scene, you meter accordingly, then put it on M with those settings to make sure it doesnt change because of other things in the scene that would change the meter reading. that sounded confusing....like say you were photographing a person on white snow and you want the person in the right of the frame. on av mode, if you put the person on the side, the meter would meter the snow, underexposing the scene. if you meter the person the put it on M with those settings, you dont have to worry about the settings changing to meter the snow.

sparky · Nov 10, 2005

darich said:
I recently bought a book about exposure in photographs. In the book, which contains some stunning and well exposed shots, the photographer said that he uses "M" mode all the time. He sets the aperture manually, then adjusts the shutter speed until the camera tells him the exposure is right.
I totally understand how that works and the relationship between aperture and exposure.
However, am i missing something by not understanding the difference between his method and Av?
When using Av doesn't the camera adjust the shutter speed automatically to suit the manually chosen aperture? If so, then it's quicker than using "M" mode.
My understanding is the same with Tv mode except in this mode, the photographer manually sets the exposure and the camera adjusts the aperture automatically.
Can anyone explain to me why he, or any photographer, would use "M" mode when not looking to alter the exposure of an image?

The answer is that there is no reason for him to use M mode. Some photographers seem to be of the opinion that because they use M mode over Av/Tv modes, they are doing something different, something better. Of course they are just doing exactly the same thing as the priority modes, but taking longer to do it!

You are correct in that M is most useful for when you want to alter the exposure from that which the camera suggests (although simply changing the EV is usually a quicker way to do this.)

thebeginning · Nov 10, 2005

sparky said:
The answer is that there is no reason for him to use M mode. Some photographers seem to be of the opinion that because they use M mode over Av/Tv modes, they are doing something different, something better. Of course they are just doing exactly the same thing as the priority modes, but taking longer to do it!

You are correct in that M is most useful for when you want to alter the exposure from that which the camera suggests (although simply changing the EV is usually a quicker way to do this.)

yep. there's more of a point to use M when shooting film than with digital too, in my opinion. with digital you can just bracket alot or bracket a little (or not at all) and shoot RAW.

JamesD · Nov 10, 2005

This might shed some light on it... although it appears to be keyed to a particular camera. The basic information still applies.

http://www.cs.mtu.edu/~shene/DigiCam/User-Guide/950/aperture-priority.html

sparky · Nov 10, 2005

JamesD, I don't think the OP was suggesting that he didn't know how to use either of the modes, but was curious as to to why the photography was using M mode then simply adjusting the settings until he got 0 EV when there is a much easier mode to use for this purpose.

danalec99 · Nov 10, 2005

M is my preferred mode.

But when it comes to assignments like weddings, when you have multiple cameras on your body and when the lighting changes every often, it is the Av mode that I rely on. Lock the focus, recompose, fire and move on.

Try all the modes and pick your comfort zone.

danalec99 · Nov 10, 2005

thebeginning said:
like say you were photographing a person on white snow and you want the person in the right of the frame. on av mode, if you put the person on the side, the meter would meter the snow, underexposing the scene. if you meter the person the put it on M with those settings, you dont have to worry about the settings changing to meter the snow.

Lock the focus on the person, recompose, you will be exposing for the person, in Av.

photogoddess · Nov 10, 2005

I generally use Av mode but do switch over to full manual on occassion. Some scenes just a little more control or tweaking that you only get with manual mode. As Hobbes said, it really does make you think about the shot before you take it. :mrgreen: