24-70 f4 is or 24-105 f4 II dilemma

Started Feb 21, 2018 | Discussions thread
OP maboleth Contributing Member • Posts: 692
Re: 24-70 f4 is or 24-105 f4 II dilemma

Ed Rizk wrote:

Steve Balcombe wrote:

maboleth wrote:

Steve Balcombe wrote:

Alexsfo wrote:

I have never observed this phenomenon on 5div but I don’t use it for macro where the effect may be more noticeable. Certainly at portrait and landscape distances there are no issues. I wouldn’t be surprised if newer Canon bodies have it in their firmware to compensate for the shift automatically.

Once again - it occurs even in manual focus.

Well, Bryan from The Digital Picture said that focus shift shows its face in MFD 70mm and advised everyone to use macro mode for close(r) work.

That's my recollection too, but as I said in my other post I ought to do a more comprehensive test. It would be useful to know exactly what I can, and cannot, get away with instead of just avoiding all close-up usage as I do now.

Also said that at ~1m at 70mm, DOF covers most of the focus shift work.

That may be why I haven't noticed the problem. I can think of cases where it may have happened.

Yeah, I'm not very sympathetic to that view. If I focus on a specific one of a group of mushrooms for compositional reasons I don't want the actual focus point to be on a different mushroom, even if the intended one is 'acceptably sharp' by some definition.

Interesting. I have always attributed any missed focus to my own lack of skill and eye hand. Still,

For many types of photography there is so much depth of field that focusing accuracy may not be too critical, but in macro work it often is - an error of a couple of mm could be too much.

Would you have to be using a tripod to get that level of accuracy? I generally don't use one with this lens.

The worst case I measured was back-focused by a couple of centimetres.

That could affect even my hand held shots. Does it happen in Macro mode or only in "regular" mode? The above implied that it didn't.

Is the difference consistent? Is it practical to simply eye ball the focus difference?

I don't know what to say, since I haven't tested the lens, but this could make me very annoyed. Because in my 7d2 I used 17-50 f2.8 Tamron a lot and doing MFD ~ 50mm was very common for me.

Yep, I have a Sigma 18-50/2.8 'Macro' which has given great service and has *zero* focus shift. It's probably my most cost-effective lens purchase ever!

Sure this lens has a specialized macro mode, but still, I wouldn't want to worry about focus shifting at, say 5.6 or f8 ~70 MFD because of this "feature". :-/

That was significant in my decision. I just have to figure out if the problem warrants replacing the lens, probably with two others.

From what I've read again, in various places, focus shift error was greatly exaggerated. Most people said they didn't even know what FS was, even though they owned the lens for couple of years.

If you go to https://www.the-digital-picture.com/Reviews/Canon-EF-24-70mm-f-4-L-IS-USM-Lens-Review.aspx and check his sheet music print you will notice that in the worst case, FS makes the original focus point only slightly blurred at 70 MFD from f4 -> f8. However, it still remains reasonably sharp, sort of like slightly missed focus point, but still having the image perfectly usable. And that's the worst possible case.

Also, if you shoot macro, you use dedicated macro mode at close distances - FS should NOT be present there at all.

After all, I will bite the bullet and buy this lens. I cannot afford 24-70 f2.8 II (plus it does not have an IS, which I always find handy anyway) and many agree that 24-70 f4 has the best IQ of all other similar-ranged zooms and very close to its older f2.8 II cousin. For 680 euros I think that will be good deal for this stellar lens.

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