A better understanding of lenses and ISO

[Trevor Ash]

Hi Again!

Therefore, if my understanding it correct (and I am not convinced it is), with Lens 1, you may need to increase the ISO rating in the camera in order to achieve the same level of image brightness as using Lens 2 because Lens 2 is a 'faster lens' and handles low light conditions better than lens 1.

This is correct.

Yes, one way to compensate for a lens with a smaller max aperture is to use a higher ISO. I was just trying to point out that while the exposure level would be the same if compensating for a slower lens with a faster ISO, other qualities of the photograph will be different.

But it seems to me that with a faster lens you may not need higher ISO levels to get acceptable photos without noise

This is correct.

Everything in photography is a tradeoff

It sounds like you need to decide whether the tradeoff for saving money by buying a slower lens (but compensating for it by using a faster ISO) is worth the disadvantages. Most of the advantages/disadvantages are in my first post.

[deekay]

thanks very much for the answers guys

It seems to me that buying a DSLR camera in what could be considered a transition period in camera history (ie., now) is a difficult proposition. For example, the new 4/3 format may be equivalent to the change from medium format to 35mm decades ago, or it may be a dead end. Who knows what form of direction the DSLRs will actually take?

my needs are for something light and easy to carry travelling that can be set up quickly for panoramic photography, amongst other things. The plan is to print the images on rolls up to A4 width, but longer than A4. My current camera cannot produce images that you can print to this size.

At least I now have a bit more usable information to make an informed decision.

thanks again
deekay

Hi Again!



This is correct.

Yes, one way to compensate for a lens with a smaller max aperture is to use a higher ISO. I was just trying to point out that while the exposure level would be the same if compensating for a slower lens with a faster ISO, other qualities of the photograph will be different.



This is correct.

Everything in photography is a tradeoff

It sounds like you need to decide whether the tradeoff for saving money by buying a slower lens (but compensating for it by using a faster ISO) is worth the disadvantages. Most of the advantages/disadvantages are in my first post.