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ISO auto or ISO manual? (1 Viewer)

Johnno65

Member
Hi,
Please could I have some opinions or wether using ISO on auto or manual control when in apperture mode or shutter mode is best practise !

Many thanks Johnno65
 
Hi,
Please could I have some opinions or wether using ISO on auto or manual control when in apperture mode or shutter mode is best practise !

Many thanks Johnno65
Depends on the Camera, your method of shooting (pod or hand held) and lens you are shooting Johnno. With the 40D auto ISO was cr#p but on the 7D it is great for bird photography, it is one less thing to worry about in the field.

With the 7D and handholding a non IS lens like the 400/5.6 it is a god send as you can use Tv mode to control the shutter speed and let the ISO take care of its self. When you use auto ISO in TV mode on the 7D almost always uses a wide open aperture which is great for a lens like the 400/5.6 but not so good for lenses that need to be stopped down.

In AV mode and Auto ISO the shutter speed returned is around focal length x crop factor of the Camera so with a 400mm lens on the 7D it returns a shutter speed of around 1/640sec - if this suits you needs then great but obviously no good for things like flyers where you need a faster shutter speed.

BTW on the 7D you can dictate the max ISO used in auto ISO by setting the max allowed in the menu.

When you use auto ISO the Camera will use 1/3 stop ISO's even if you have your Camera set for full stops only. A few years ago some intermediate ISO's were considered to be nosier than the next up full ISO but nowadays the algorithm used to calculate expose with these intermediate ISO has got a lot better and I have not problems whatsoever using intermediates.

For crop Camera's other than the 40D and 7D I cannot comment on how good or otherwise auto ISO is has I have no experience.

Hope this helps John.
 
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