Nikon 14-24 focus shift

[Jan Brittenson]

I just took a look at my 14-24 since I had never noticed a focus shift. I have it AF tuned for f/5.6, and it has always behaved very predictably to me. It does seem to shift ever so slightly at f/2.8 from 14-16mm. But the lens also softens slightly, so it's hard to tell what's what. At 18-24 I see no focus shift at all. I also can't tell f/2.8, f/4, and f/5.6 apart at center - they look identical to me, at 100% with my glasses on, critically pixel peeping. At 16mm I can tell a difference when flipping between f/2.8 and f/4 test shots, but it's a very very slight difference. It's a lot more obvious at 14mm. At 14mm I can also tell the focal plane shifts between f/2.8 and f/4, ever so slightly.

This was shooting with a LensAlign Mk2 at a close enough distance to fill the center spot indicator in the viewfinder, about 5-10 feet. I think it's reasonably representative for how I use it as well. I very rarely shoot wider than 18-20 and then only on even rarer occasions wider than 16. For non-people shots it's exclusively used stopped down to f/5.6 or further as DoF mandates. I never use live view with this lens, but for static subjects will make a best guess and make adjustments from there. Sometimes for long exposures that makes this prohibitive I'll crank up the ISO for shorter test exposure for DoF and focal adjustments, then make the long exposure at ISO 100.

Basically, within my uses it just works... I never have to consider focus shifts. Not a problem for me at all.

 

[danielmoore]

I have the first version of the Fotodiox filter adapter and it's lives on my 14-24. I have the fiddly metal screw on lens cap as it's V1. Having a polarizer for my interior work has been invaluable.

 

[Rethmeier]

I use the Fotodiox filter adapter as well.

Can I ask a silly question, how do I check if my 14-24 has focus shift issues?

It's my most used lens.

W

 

[Leigh]

Just posted a update on the Leica 19mm R lens in the review section.

19mm is not 14mm... not even close.

- Leigh

 

[danielmoore]

Rethmeier, here's a brief but good read on the subject:

diglloyd - Focus - Focus Shift and Spherical Aberration

If you're using Live View, as Guy has stated, you may not ever come across it as you're then confirming focus on the desired point. I think focus shift with the 14-24 is a given, not some sample variation. You could see for yourself by using the viewfinder and autofocus at aperture f/2.8 on a subject relatively close and do the same @ f/8. With this and most affected lenses the focus will shift forward at f/8. In my interior work I always use live view to focus and typically stick to f/11 and it isn't an issue this way, which might explain why you may not have found it to be a problem in your work.

 

[Guy Mancuso]

19mm is not 14mm... not even close.

- Leigh

No its not 14 nor is it 24mm but what it is, is what the 14-24 can't do is render a much nicer look. I have had everything here except the Zeiss 15 and nothing under 24mm can render a look like the 19mm. Depends on what your after and your needs obviously but going through every Zeiss and every Nikkor under 24mm I'm sticking with the 19mm and build around it. Also I'm not a zoom guy and that explains some of this.

The 14-24 is a nice lens but also has some downsides as well, heavy, big, focus shift and won't take filters. For a lot of folks its not practical to there needs.
Horses for courses

 

[Rethmeier]

Rethmeier, here's a brief but good read on the subject:

diglloyd - Focus - Focus Shift and Spherical Aberration

If you're using Live View, as Guy has stated, you may not ever come across it as you're then confirming focus on the desired point. I think focus shift with the 14-24 is a given, not some sample variation. You could see for yourself by using the viewfinder and autofocus at aperture f/2.8 on a subject relatively close and do the same @ f/8. With this and most affected lenses the focus will shift forward at f/8. In my interior work I always use live view to focus and typically stick to f/11 and it isn't an issue this way, which might explain why you may not have found it to be a problem in your work.

I always shoot at F10 and don't use Live view , but I'll give it a try antway.

 

[Rethmeier]

No its not 14 nor is it 24mm but what it is, is what the 14-24 can't do is render a much nicer look. I have had everything here except the Zeiss 15 and nothing under 24mm can render a look like the 19mm. Depends on what your after and your needs obviously but going through every Zeiss and every Nikkor under 24mm I'm sticking with the 19mm and build around it. Also I'm not a zoom guy and that explains some of this.

The 14-24 is a nice lens but also has some downsides as well, heavy, big, focus shift and won't take filters. For a lot of folks its not practical to there needs.
Horses for courses

It does take filters. I use a polariser on it all the time when I shoot interiors.

 

[danielmoore]

Technically, it can't take filters, but it can take filters with more money, and more size. : )

I only rarely use it wider than the fantastic 24mm end. Not much liking the 3:2 format the 19mm, cropped at 4:5 would suit me just fine. Saving up.

 

[fotografz]

If focus shift is a given as suggested, it seems that firmware could be a solution ... at least with-in some level of tolerances.

The reason that I mention this is that the Hasselblad H camera's True Focus (not to be confused with TF Absolute Position Lock), uses mapped lens responses in camera to correct for focus shift for each of their lenses. As you stop down, precise focus corrections are made for focus shift to maintain the original plane of focus selected by the photographer. I believe this is true even for their zooms.

I think this is a real possibility if Nikon continues its foray into high resolution photography with more demanding applications. Whether they'll do it or not is the question ... but it sure seems a lot easier than trying to design lenses that can keep up and the expense that entails.

Just a thought.

- Marc

 

[AreBee]

Daniel,

...most affected lenses the focus will shift forward...

Rearward. In other words, farther from the photographer.

Marc,

If focus shift is a given as suggested, it seems that firmware could be a solution ...

...the Hasselblad H camera's True Focus...uses mapped lens responses in camera to correct for focus shift for each of their lenses.

My understanding is that Leica S system lenses also take into account focus shift via firmware. It's a great idea.

 

[danielmoore]

Thanks Rob, of course you're right. I was thinking of the counter measure which I have burned in my brain.