“This Lens is Soft”…

[jonesgj]

I read this article on the Canon Rumours site regarding 'soft-focus' a few minutes ago which some may find interesting. It's not a new article but I have seen a few posts recently regarding whether a lens is soft or sharp, and this seems like something that should be taken into consideration before using a broad brush to describe the quality of all examples of one lens when tested on one body.
Regards
Graydon

[briansquibb]

Re: “This Lens is Soft”…

I was having this 'soft lens' problem as described in the article on my 50d. I then set up the microfocus - and now all my lens are spot on. I assume that the camera was out and that my adjustment brought it back in the middle - look at my dragonfly in the macro forum to see how sharp it now is.

Brian

[Jules]

Re: “This Lens is Soft”…

Read that article myself a couple of weeks back when I was having so much trouble with my 10-22, unfortunately for me, no amount of in Camera Focus Adjustment would have cured it! I'ts a useful tool but you need to know what your doing with it I think. The secret as it says is not to just do one set and take that one as read so to speak but three to make sure of what your'e seeing. I'm not a great tester and my patience is lacking here I have to say but I have it in mind to see how my 100-400 does soon...

[Muscat]

Re: “This Lens is Soft”…

Interesting article which makes, to me anyway, perfect sense if you want 100% then you need to have very very deep pockets if it can be made.

One thing that I have never been sure about is on a zoom lens when adjusting the microfocus settings where in the zoom range do you do that?

[MX5]

Re: “This Lens is Soft”…

The Canon DLC has an article AF Microadjustment which is a good place to start.

But also you need to ensure you have your focusing set up correctly Canon guide to Accurate AF before you start tinkering

[Muscat]

Re: “This Lens is Soft”…

Hi MX5, thanks for the links, I had read these previously but none of them actually suggest where is the best place to set the microfocus on a zoom lens, this is an extract from the Canon website

"If you're using a zoom lens, zoom to its maximum telephoto focal length for test pictures. AF Microadjustment can only apply one correction to a zoom lens, so you cannot have one adjustment for the lens's wide-angle setting and another one for the same lens when it's zoomed to telephoto"

I therefore would suspect that the zoom would be adjusted at the focal length that shows the most 'softness'. However if you adjust this focal length I assume that it will have an effect either good or bad on the remaining focal lengths. In which case it may simply be best to say OK I will work around any 'soft' spot with the lens.

As it happens at this point in time I am happy with the sharpness of my zoom lenses and don't believe that I need to adjust anything for them, my query was simply one of curiosity

[MX5]

Re: “This Lens is Soft”…

I think as focusing becomes more critical at the long end (as DOF drops off) then that would be the place to set microadjustments. I suspect if a zoom lens has a none linear behaviour in focusing issues then it needs Canon to fix it.

I did play with microadjustments with my 7D+300L ... just to see what they did. In the end I cancelled the microadjustments. But it was an interesting excercise (to some extent!).