D7100 Inconsistent Focus Tracking Errors

mikew_RIP

Senior Member
That's effective aperture not selected. I don't see how that is a problem with faster lenses? I'm not familiar with the D7000 but I'd be surprised if it can focus at f/8 (effective aperture) even when only using the center.

The others are FX so you can't really compare them.

I checked Nikon to see which cams can AF up to f/8:



As you see, the D7100 is actually an improvement on the D7000.

That saved me some research :D,i find the D7100 next to useless for tracking oncoming BIF,would have considered a D7000 if it had a better AF although it doesnt handle noise as well.
 
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In my photographic world the 7100 is inferior to the 7000 in focus performance and I just use the figure quoted as a guide to ability to focus ..Clearly I dont use an F8 lens (140mm 3.5-5.6) .I can only speak as I find.D7000 never a focus hitch D7100 pain in the butt.
 

J-see

Senior Member
In my photographic world the 7100 is inferior to the 7000 in focus performance and I just use the figure quoted as a guide to ability to focus ..Clearly I dont use an F8 lens (140mm 3.5-5.6) .I can only speak as I find.D7000 never a focus hitch D7100 pain in the butt.

Since your photographic world doesn't seem to match the rest of the photographic world, it might be good to check if either the lens or cam has some issue or needs fine-tuning. It's always possible you got a Monday morning version. It could be something that's easily fixed.

https://photographylife.com/nikon-d7100-vs-d7000

The biggest difference between the two cameras is the autofocus system – the Nikon D7100 has the excellent Advanced Multi-CAM 3500DX autofocus system, which is basically a tweaked AF system from the Nikon D300s that can handle lenses up to f/8. The D7100 will have 51 focus points with 15 cross-type points, which is a big jump from the Multi-CAM 4800DX on the D7000 with 39 focus points (9 cross-type). This makes the D7100 much more suitable for tracking subjects, photographing in low-light environments and using teleconverters with telephoto lenses.
 
Well we have two views here ..one (not me ) says its a PITA and I agree and one says I am in another world....That world consists of churches and reception venues ...one not always with low light and another where its normal room lighting . I have two D7100 and both give the same problem... The single AF point in the 7100 is not assisted by other points and I think thats the problem. Low contrast rather than low light seem to be the problem .The D800 gives no problem but it too noisy to use.
Looking for someone who uses the D7100 in anger and has no problem to tell me how its set.
 
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J-see

Senior Member
The single AF point in the 7100 is not assisted by other points and I think thats the problem.

That single focus point is only when you attach something to the cam lowering the effective aperture to f/8. An f/4 lens with a TC2x attached as an example. It's not relevant with normal lenses since then you have all kinds of options to focus.
 

Paganman2

Senior Member
That single focus point is only when you attach something to the cam lowering the effective aperture to f/8. An f/4 lens with a TC2x attached as an example. It's not relevant with normal lenses since then you have all kinds of options to focus.

I too agree with this - if you use Any lens with an effective widest aperture of f8 or wider, you can then select up you 15 cross type sensors in the central area all working together, by using the 21 section dynamic focusing setting, or just 9 cross type or even just the one at the very center or moved around through the 15 cross types at your choice.

P.
 

Paganman2

Senior Member
What i will add to this - I think the 1.3 crop mode in the camera makes a negative difference to the focusing accuracy, for reasons unknown...

P.
 

mauckcg

Senior Member
Well we have two views here ..one (not me ) says its a PITA and I agree and one says I am in another world....That world consists of churches and reception venues ...one not always with low light and another where its normal room lighting . I have two D7100 and both give the same problem... The single AF point in the 7100 is not assisted by other points and I think thats the problem. Low contrast rather than low light seem to be the problem .The D800 gives no problem but it too noisy to use.
Looking for someone who uses the D7100 in anger and has no problem to tell me how its set.

Define used in anger? The best I can do is continuous shooting, 9 point AF-C, up to ISO 3200 depending on how late it is and the ambient lighting at the track.

The only issues I have are when there is a fence between me and the moving subject and the D7100 will grab focus onto the fence for several frames.
 
I talked to another professional who used the 7100/18-140 in the same situation as me and has no problems. So I changed two things when I went from 7000 to 7100 the body and the lens. Now I dont remember a problem with the sigma 18-270 focus wise and both 18-140 were from the same grey source . So first order is to try another lens. I have 28-300 Nikon so will try that and compensate for the 28mm with the D800 and 17-35 which I always carry.
What do I mean by using it in anger ??? At a wedding where the d@m thing has to fire when you pull the trigger!!
Will let you know after the next wedding which has the rings delivered to the best man by an owl.....thats using it in anger ..no second chance !!
 
After 40 years I know what is right ...sounds like you dont have to keep a bank manager happy.
Requirements
24MP +
18-140mm or more
Light on the neck and the bank balance....
You can see no difference between my D7100 and D800 shots and the customer certainly cannot.
 

J-see

Senior Member
If you are satisfied with your kit, who am I to disagree but you can't put slow lenses on a DX during low light situations and then expect miracles.

That's why they sell fast lenses for FX low light performers.
 
Thats why you should never mention the W word on a forum ..does not matter how fast the lens is you still got to be at F8 if you want sufficient depth of field to cover 4 people standing in a line at 45 degrees to you. and they dont make a suitable FX lens for weddings other than the 28-300 and thats 3.5-5.6 .
Will not comment furthur until I done some tests with other than the 18-140.
Thanks for your input.
 

J-see

Senior Member
Thats why you should never mention the W word on a forum ..does not matter how fast the lens is you still got to be at F8 if you want sufficient depth of field to cover 4 people standing in a line at 45 degrees to you. and they dont make a suitable FX lens for weddings other than the 28-300 and thats 3.5-5.6 .
Will not comment furthur until I done some tests with other than the 18-140.
Thanks for your input.


Fast lenses have nothing to do with the aperture you set. They're fast because they always AF at their effective aperture. My f/2.8 will always focus at f/2.8 even when I set the aperture to f/32.

When you attach a lens, it is wide open and will not close down to the selected aperture until you take the shot or push the Pv button to check DoF.

There aren't many that go from the very short to the medium range but you might want to check out the 70-200mm f/2.8 lenses. They're not the cheapest but very, very good.
 
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70-200 at a wedding ???? How far back do you think I stand during the service ??? 15ft ....4 people full length with a 70 mm ??? speeches maybe ..oh and I never change lense or carry a shoulder breaking bag..
I have already suggested we cut this discussion for fear of upsetting the moderator.
 

J-see

Senior Member
Why would we upset anyone? We're just talking and I pointed you to a lens that's probably in about every wedding kit.

But if you shoot weddings with one lens that covers all, there's no need to continue.
 

mauckcg

Senior Member
70-200 at a wedding ???? How far back do you think I stand during the service ??? 15ft ....4 people full length with a 70 mm ??? speeches maybe ..oh and I never change lense or carry a shoulder breaking bag..
I have already suggested we cut this discussion for fear of upsetting the moderator.
Then get a 17-50/55 2.8. The point is, faster glass focus' better and faster than the variable aperture kit lenses. Even the sigma 17-70 2.8-4 would be an improvement.
 
If you know anything about the current format of english weddings you know there is no time for lens changes tripods remote flashes or bags of kit ..I carry one D800 with 17-35 (a very noisy camera only usable during hyms) and a 7100 with a 18-140 (used a sigma 18-200 previously but it causes LCD problems) spare batteries in the grips etc and of course a megaphone.
Between the two of us we are taking about 1500 shots at a full wedding ..everything taken twice at 1/2 second interval to a void blinkers and tongue twitches . they get about 800
So go work it out ..where is the time to fiddle with lenses?? 60 weddings a year ..somebody must be happy.
I dont have any problems with focus in discos as I bring my own portable lazers/led projectors all battery operated in a small case and by the time the DJ has worked out whats happening I have gone...all good fun
 
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