D7100 focus issues

Pistnbroke

Owned a couple of D7000 and had no problems with focus but the D7100 ( I have two) gave immediate problems in situations the D7000 did not.
I use AF-S ( 5) release on focus ..pick an edge focus re frame and push.....Often the thing just will not release the shutter or if you hold down will fire after maybe 1 second ..too late the shots gone ...not particularly low light....any suggestions ??

Ironheart

Are you sure you actually obtained focus on the first half-push? Did you hear the beep and/or see the green dot? Once it's locked it should fire immediately. What does ( 5) mean in your description above?

Pistnbroke

Well its the delay in getting a lock that is the problem...you can in AF-S select auto or 5 ...auto give you focus points all over the place only " 5" gives you one in the centre ....you all tell me thats why I am asking...

Ironheart

Ha, well that's supposed to be an "S" for single, that's why the 5 threw me off. So you are doing the classic focus and re-compose. There are three steps, 1) lock focus on an edge/eye/whatevs 2) move/recompose, 3) release

Are you saying you never get lock in step one? Do you let-up on the shutter losing the lock in step 1 before getting to step 3? You're not describing the problem well enough to help troubleshoot.

Pistnbroke

well I was never sure if it was S or 5 but there is it ...I try to lock on and edge but often with what I think is a lwell lit contrasty edge it just wont have it ...my wife has he same problem ..if I shoot the same senario with the (horrible) D800 no problem ...just wondering if others have the same problem or if there is a soluton.
Nice Ironheart for you to try to help ( not buying a D7200 as I have no buffer problems !!!)

manhattanboy

well I was never sure if it was S or 5 but there is it ...I try to lock on and edge but often with what I think is a lwell lit contrasty edge it just wont have it ...my wife has he same problem ..if I shoot the same senario with the (horrible) D800 no problem ...just wondering if others have the same problem or if there is a soluton.
Nice Ironheart for you to try to help ( not buying a D7200 as I have no buffer problems !!!)

Use the autofocus lock button.
See this article for more ideas on how to deal with this problem:
https://photographylife.com/nikon-ae-l-af-l-button

Also, I always shoot AF-C, but you can change it (see the manual) to fire once regardless of focus with subsequent ones requiring focus. That may help the timing issues as well so you don't miss the shot.

Ironheart

If @Pistnbroke issue is that the camera wont get a focus lock, then it probably won't matter which button is pushed, whether the half-press of the shutter or the AF lock. @Pistnbroke, are you using the center point or a different one? The center point is a low-light cross-type focus sensor, the 15 in the center are cross-type but not as sensitive to low light. Make sure you are on the center point and then lock your focus point selector knob.

Photobug

+1 to what @Ironheart said.
@Pistnbroke - I don't remember having this issue with my D7100, based upon 18 months of use.

Pistnbroke

yes centre point for certain..will check into manhattenboy suggestions but what gets me we never had this with the D7000....

KnockKnock

Another +1 to Ironheart's. In good lighting, I have no problems with the side AF sensors but in low light I use the middle focus sensor and recompose. I think the intent of the outer sensors is to avoid recomposing. If your style is to focus then recompose, best use the middle sensor/s.

Check the manual page 37 section 5 to make sure you understand the In-focus indicator. That will help figuring out what's going on. If it's lit, you should get immediate release.

Next, check your settings for how the camera prioritizes shutter release vs. locking on to focus. Manual page 231. Read it carefully. You can set it to "release" any damn moment you push the button, but the consequence is you may get an out-of-focus picture.

If you know you have focus lock and you understand how your AF priority is set, then you'll be on your way to knowing if your camera is working properly. It's possible the D7000 was setup for release priority.

Pistnbroke

Followed the links above and studied the information but did not really learn anything I did not know. Did various tests and concluded only AF-S was suitable for my needs but did get one idea...
Now when this happens I am not using a flash gun with IR beam (flash not permitted in church) so I thought why not fit a IR light to the camera ? The minister cannot see it so no problem ...I have a 64 led video light which I dont use so have ordered 100 IR leds and will change the leds on the unit and just leave it on during service Not sure if this would colour the picture but at 3w its not a lot of illumination
Will let you know slow delivery from Guandong ....

spraynpray

Surprising read @Pistnbroke. During my pre-pirchase trial I found my D7000 would take two or three attempts to focus a 50/1.4 and given the exact same lens and subject framing (tripod not moved) a D7100 absolutely snapped to focus. I use centre point AF-S and recompose in church too.

Pistnbroke

Exactly spraynpray that is why I thought I would share the problem to see if I can find a solution..
but it will be an 18-140 at 100-140 that gives the problem..50 mm is not use to me at any time in a wedding.

Ironheart

Just do me a favor, pull the gaffers tape off of the controls and make double sure you have the center focus point selected. The center point is good for f/8 and the other 14 points in the middle are only good for f/5.6

manhattanboy

Exactly spraynpray that is why I thought I would share the problem to see if I can find a solution..
but it will be an 18-140 at 100-140 that gives the problem..50 mm is not use to me at any time in a wedding.

Something is off. The 7100 focuses using the center point only very well. Try another lens as it may be a lens issue...
All else fails then use the flash in IR assist mode:
http://www.dpreview.com/forums/post/52731001

Pistnbroke

Iron heart ..after 40 years and being a member of MPA BIPP and RPS I think I can work out which is the centre focus pint ....The D7000 used Sigma 18-200 and 18-270 which will not work with the D7100 but we remember no problems. I can try the 28-300 nikon but these situations are difficult to simulate usually happening in the middle of a wedding service or speeches. I was not aware that I can use the flash IR af assist without the flash function ..will check that tomorrow.
What I am looking for is someone to say I had that problem and I cured it like this .
SU 800 thats a thought

Ironheart

@Pistnbroke, no worries, focus points sometimes seem to have a mind of their own...
Do you have any filters (clear or otherwise) on the lens?
Perhaps the AF assist lamp was turned on with the D7000 but not on the D7100?

heartyfisher

The weaker AF in low light of my D610 has got me looking for solutions for AF in low light too and when I was considering the Df (I needed off camera flash) .. The SU 800 has been suggested to me but its too expensive to buy to "try" however I have been investigating the SU-800 clones. and the DEBAO gets good reviews .. http://www.lightingrumours.com/debao-su-800-st-e2-have-longer-range-than-the-real-thing-4205

Ironheart

The SB700 and SB900 both have the focus assist as well if you want to mess with it. It is however not really "infrared" but red visible hash marks. Ditto for the SU800.

Pistnbroke

Thanks everyone for there help and interest .
Well I conducted some more experiments ..if you have a black white edge transition then the focus works fine. but if the transition is mushy then no autofocus.
We conclude that the IR AF assist being off centre from the lens casts an IR shadow which gives sharpe edges to focus on .....The hash mark idea means they are projecting a target onto the subject ..interesting.
UV filter causing a problem ..will look into that ...
Re SU 800 ( or YN 560TX) if you fit it I assume the ISO gets locked at 4x the base camera iso ..thats what happens when you turn a flash on ....so thats no good.( typically looking at 2500 ISO @f8 in a bad church ) Think we come back to the IR light on all the time ...maybe the 64 led one off one side of the top table would throw IR shaddows with sharpe edges to help the focus mechanism.... still waiting for the leds from HK but have the unit dismantled and does not seem a problem to change the 64 leds think I will leave one of the originals so I can tell its ON !!! ( they seem to sell these IR units for Ghost Hunting ..??? !!! )

spraynpray

@Pistnbroke - f5.6 is out of the question?

Pistnbroke

I follow you Spraynpay but that does not affect the focus as the lens is wide open.....
However investigation shows that the AF assist on a flash gun IS A LAZER not IR .
turn on AFS AF assist on in menu ..fit SB900 or YN565 hand over lens and half press ....with the YN you get about 25 horizontal and vertical bars on the wall .....has to be a lazer to keep such a well collimated beam.
Now so the vicar says you can use flash you zoom in on the rings or faces and put a huge lazer sight on the couple !!!! OK only for a fraction of a second but I think they would notice !!!
Still does not solve the problem of a reasonable amount of light but very difussed and all mushy white edges.
Dont like hammerheads (never used the Yn565 in anger) but will try it at the next set of darkish speeches.
Oh what fun this photography.

heartyfisher

I am curious to see if the IR lamps work for AF assist. There are a couple of issues I would test...

1) IR can be seen with the sensor. You can take a photograph of a TV Remote bulb and see if its on or off.
2) The AF may see the object at the wrong distance. in the old days of IR photography we had to focus in normal light and then move the focus ring by a certain amount to shoot in IR.
3) Not sure if the AF sensors work with IR. Can it see IR?

Pistnbroke

Well the Lazer is putting a sharp edged pattern on the object to be focused on ..I suppose the IR could throw shaddows in the ruffles of a white dress but those 100 IR diodes are a couple of weeks away .
Have ordered a lazer with a cross hair and a diffractin grating ..not too difficult to trigger the lazer from the built in focus assist light BUT if its so light the assist does not come on and you have no contrasty edges you are sunk.
All the focus Asist devices using lazers SU400 yn560tx and yn622n all stop the auto iso working which is a pain.
Have consecutive three weddings soon but have other problem photographs like the rings are being flown in to the best man ...by an Owl ...........

Photographed a night vision camera ..yes the IR is visible and red but not strong

manhattanboy

Well the Lazer is putting a sharp edged pattern on the object to be focused on ..I suppose the IR could throw shaddows in the ruffles of a white dress but those 100 IR diodes are a couple of weeks away .
Have ordered a lazer with a cross hair and a diffractin grating ..not too difficult to trigger the lazer from the built in focus assist light BUT if its so light the assist does not come on and you have no contrasty edges you are sunk.
All the focus Asist devices using lazers SU400 yn560tx and yn622n all stop the auto iso working which is a pain.
Have consecutive three weddings soon but have other problem photographs like the rings are being flown in to the best man ...by an Owl ...........

Photographed a night vision camera ..yes the IR is visible and red but not strong

I still think it is partially caused by the lens... for example on the same lens you are only having trouble once you get to the tiny minimum aperture range at the end of the zoom. Could you borrow a 2.8 zoom and try?
Also, you can always try switching to live view and using contrast detection if the phase detection is having trouble picking out lines to focus on.

Ironheart

FYI, the hash-marks are not produced by a laser, just a bright LED. The distance falls off pretty quickly 15-20' is max. If this works for you, this is a cheaper way to go ($72):
http://www.bhphotovideo.com/c/product/300478-REG/Nikon_4766_SC_29_TTL_Off_Camera_Shoe.html