Faulty camera or faulty user?

[The Stig]

I've noticed a few times that my D90 misfires - that is, it seems to misfire, then you end up taking a picture of yourself staring into the lens wondering what the hell went wrong. I've had it in the shop where they replaced the contact points, or something. Today it happened again. This evening I thought that I'd try to find out under what circumstances it'd misfire. It turns out that it never (at least I haven't managed to get it to misfire so far, having fired of 75+ pictures) when it's in manual focus. This leads me to believe that it may be just a case of AF indecisiveness (busy, contrast-rich backgrounds etc). Does anyone have similar experiences?

Any input would be greatly appreciated.

Cheers,

Stig

[Donald]

Stig

At the risk of seeming to insult your intelligence - Is it happening when you are in one particular mode? You say it doesn't happen in Manual. But when does it happen?

And, if so, check that the particular mode doesn't have the Drive Mode defaulted to a timer delay setting?

[Dave Humphries]

Hi Stig,

My first thought was the self timer (2 or 10 seconds from memory).

However, your description of a lack of focus lock causing it, would only do so while you finger remained on the shutter button and if you turned the camera round to look down the lens, I doubt that'd still be the case.

Only worth looking into AF modes more if you still had your finger on the button, if you didn't; then self timer, intervalometer(?) or it is faulty.

Can you try another lens?

[The Stig]

I may have been less than precise in my description. It does happen in manual and aperture-priority mode, but only when I use AF - I don't have proof of concept in MF. What happens is I'll take, say, three pictures. The first and second will fire without strangeness, but the third, or fourth, or fifth might delay a second before it fires. Just enough time to ruin the composition or scare away whatever rare specimen you're trying to shoot. I thought initially (earlier today) that it could have something to do with the actual button, but I haven't been able to replicate this at home this evening. It's very frustrating because it's so intermittent. Thanks for your suggestions so far, but it's definetely not related to the self timer. It seems to me to happen to my 35 mm f/1.8, but this is also the lens I use the most, so it's difficult to say whether it's a property of that specific lens or just a higher probability of the problem surfacing with that lens.

Frustrated

[Markvetnz]

Just a few things to check. If it fires ok on the first shot and fails on subsequent shots it might just be a case of not enough time to charge. Check your shutterspeed and X sync speed of the camera. Anything over 1/200th and you might need to use high speed sync.

In my experience these little problems are most often what I call "finger trouble" and not hardware issues.

[Dave Humphries]

This now sounds like "buffer fill", with it being ok to start then slowing on third and subsequent.

Are you shooting RAW + jpg fine?

Mind you, it should be bigger and quicker than that, have you got a cheap/slow/small/full memory card in?

[MrB]

It does happen in manual and aperture-priority mode, but only when I use AF - I don't have proof of concept in MF. What happens is I'll take, say, three pictures. The first and second will fire without strangeness, but the third, or fourth, or fifth might delay a second before it fires. Just enough time to ruin the composition or scare away whatever rare specimen you're trying to shoot.

My first thought was the AF system, but this is probably too obvious (like the self-timer) to be the problem.
However, is the camera indicating that it has found the correct focus before the delay to the shutter firing? I know nothing about Nikons, but I assume that my camera is not unusual in having a setting deep in the menus that prevents the shutter firing until the image is focused.

Philip

[The Stig]

Mark: From your reply I get the impression you're referring to flash photography? This has so far not happened while using a flash. If I'm mistaken, could you explain a bit more what you're referring to?

Dave: The shutter delay doesn't appear with any sort of regularity. I had two instances relatively close to each other earlier today, but I've fired of close to a hundred shots at home for testing with maybe one or two slight delays. The rest of them were fine. I'm shooting RAW with a generously sized memory card (240 pictures to go at the time of writing).

MrB/Philip: I'm beginning to suspect something related to what I've earlier called AF indecisiveness - the AF system not managing to figure out exactly what it is you want it to focus on. The instances earlier today was with AF-A, which is - if memory serves - Nikon-speak for static focus if the subject is still, and continuous focus if the subject moves. I know that AF-S (static focus) requires focus lock before it fires, whereas AF-C (continuous) doesn't. Maybe it decided that the subject wasn't moving (which it wasn't), but failed to lock on before I pressed the shutter release fully down?

Thank you very much to all of you for taking the time to help out with my problem. I just remembered that this has happened before with another lens - a Nikkor 55-200 which I no longer have. That should clear the lens from suspicion, yes?

[PhotomanJohn]

Stig - You can control if the camera requires focus for AF-S (single) or AF-C (continuous) modes separately at least on my camera. Look up menu items a1 and a2. I would set both these options to "Release" which will disable the lock-out. This is my normal setting because I want the exposure to be taken when I push the button. I don't need the camera to decide if I know what I am doing. I normally don't use AF-A (automatic) because I'm never sure what the camera has decided to do.

John

[Shadowman]

This now sounds like "buffer fill", with it being ok to start then slowing on third and subsequent.

Are you shooting RAW + jpg fine?

Mind you, it should be bigger and quicker than that, have you got a cheap/slow/small/full memory card in?

When Dave mentioned "buffer fill" I thought about the specs for the camera which are: Continuous shooting as fast as 4.5 frames-per-second: Combined with fast 0.15ms power-up and split-second 65ms shooting lag, dramatic action and decisive moments are captured easily.

My D60 shoots at 3 fps and on the first burst will actually shoot at 4 or 5 continuous frames and then on the second burst 2 frames and then a lag, however it doesn't fire afterward until I've given it a rest.

[Letrow]

Stig - You can control if the camera requires focus for AF-S (single) or AF-C (continuous) modes separately at least on my camera. Look up menu items a1 and a2. I would set both these options to "Release" which will disable the lock-out. This is my normal setting because I want the exposure to be taken when I push the button. I don't need the camera to decide if I know what I am doing. I normally don't use AF-A (automatic) because I'm never sure what the camera has decided to do.

John

This was my initial thought as well when I read your post. AF can hunt around a bit and if the camera is set to shoot with focus only and it hasn't focused properly yet it will not release.
Single point AF will help a bit (as long as the subject has enough contrast), if you use AF-A or AF-C (auto or 3D) it may slow up.
I would keep the lock-out though. If you set the camera to shoot at Release as John recommends a lot of your photos might end up out of focus.

[Dave Humphries]

When Dave mentioned "buffer fill" I thought about the specs for the camera which are: Continuous shooting as fast as 4.5 frames-per-second: Combined with fast 0.15ms power-up and split-second 65ms shooting lag, dramatic action and decisive moments are captured easily.

My D60 shoots at 3 fps and on the first burst will actually shoot at 4 or 5 continuous frames and then on the second burst 2 frames and then a lag, however it doesn't fire afterward until I've given it a rest.

Hi John,

Yes, that's why I was trying to think of other reasons for it to kick in on only the third shot, my D5000 (same sensor and processor as D90) can easily do more far than three RAW only shots before the buffer fills/slows, so I was scratching around for other reasons; like fragmented free file space on the memory card slowing the emptying of buffer and storing more (with RAW + fine jpg) compared to my experience (and the specs).

I enjoy the fast start too

[Dave Humphries]

Stig - You can control if the camera requires focus for AF-S (single) or AF-C (continuous) modes separately at least on my camera. Look up menu items a1 and a2. I would set both these options to "Release" which will disable the lock-out. This is my normal setting because I want the exposure to be taken when I push the button. I don't need the camera to decide if I know what I am doing. I normally don't use AF-A (automatic) because I'm never sure what the camera has decided to do.

John

Hi John,

I'm not sure a1 and a2 on the D90 do the same as your D7000.
On my D5000, I couldn't see an option to override the release setting - it certainly isn't a1 (AF area mode) and a2 (AF assist illuminator).

I too avoid AF-A, I know when I want AF-C and AF-S and I set it accordingly

Cheers,

[Dave Humphries]

Hi Stig,

One more 'silly' question; I assume we're talking about 'normal' viewfinder usage, not Live View?

Do you have it set for a single focus point and no fancy focus tracking options enabled?
I assume you have it in continuous shooting mode?

Only other idea is next time it does it, check the little green LED bottom right; if out while paused, it is not the buffer.
Then try this; immediately pan to something you know it cannot stuff up focus on, keep still and keep your finger on the shutter button.

I just tried this, several times on different distance subjects, and I consistently get 5 exposures at the maximum rate, then it stops to spit them out to the SD card, if I keep my finger on the button, it takes at 1 fps thereafter. Not as sparkling as the spec. says (7), but it does for me. This with a Sandisk Ultra 8GB card (15 MB/s), not my fastest card and it has some protected files dotted across the memory map, which probably doesn't help.

Looking at the LCD shooting menu, the column of settings down the right hand side read; RAW only, Auto WB, 200 iso, continuous, AF-C, single (central) AF point, centre weighted metering, ADL off, BKT off. I suspect the D90 is similar enough to compare to mine.

It also made no difference if I was in the 'AF-ON' mode (back button focus) or normal shutter button AF initiation.

You might want to try AF-ON mode, it separates AF from the shutter button, focus once, release and it is effectively in manual focus until you refocus by pressing/holding the rear AE-L button - however, the 'focus release mode' is still operative, so if you pan to something that it judges too soft, it just won't let you take a picture at all.

While I was doing this, the battery was on its last third of capacity indicator.

One last thought; as I have a D5000, I am using an AF-S lens, the ones with the quick, built-in, ultrasonic AF motor - if your lens is an AF or AF-D, and hence using the D90's own focus motor, that may slow things down. The AF-ON check above should eliminate that variable though, if you focus once and take your finger off the back button.

Hope all that helps the diagnosis.

Cheers,

[The Stig]

Thanks for all your input. I should point out that I'm not talking about multi-frame shooting. These are all one-shot photos. I think I may have stumbled over a clue: it seems to happen when I use semi-automatic modes (AV for the most part) and use the 3D-tracking AF with matix metering. I'm going to do some tests with just centre focus point, centre-weighted metering and manual mode. Regarding the lenses they are all AF-S lenses.

Aren't you all glad that I'm keeping you from what you're supposed to be doing with my interesting problems?

Thanks again,

Stig

[Dave Humphries]

Aren't you all glad that I'm keeping you from what you're supposed to be doing with my interesting problems?

Oh yes, but my invoice is in the post for all the film I wasted this morning
That'll 'knock the grin off'

[Dave Humphries]

Thanks for all your input. I should point out that I'm not talking about multi-frame shooting. These are all one-shot photos. I think I may have stumbled over a clue: it seems to happen when I use semi-automatic modes (AV for the most part) and use the 3D-tracking AF with matix metering. I'm going to do some tests with just centre focus point, centre-weighted metering and manual mode.

I was Av too FWIW

I doubt the metering will affect it, but the 3D tracking might.

As might whether you lift off the shutter button entirely, or just release to half press, between shots 1 and 2 and shots 2 and 3. Once it starts doing a buffer purge in single shot mode, it might be reluctant to start again - just a thought.

I always shoot in continuous mode for 90% of my subjects.

[The Stig]

Oh yes, but my invoice is in the post for all the film I wasted this morning
That'll 'knock the grin off'

Yes, grin knocked off - d'oh!

As might whether you lift off the shutter button entirely, or just release to half press, between shots 1 and 2 and shots 2 and 3. Once it starts doing a buffer purge in single shot mode, it might be reluctant to start again - just a thought.

Hope I don't seem thick, but can you clarify what you mean here? I almost get it, but not quite.

[Dave Humphries]

That's another 3 rolls of 36

I also set my camera as close as I could to what we've arrived at as your shooting mode
(talk about 'pulling hen's teeth', sheesh )

So,
3D AF tracking; check
AF-A and AF-S: check
Matrix metering; check
Single shot mode; check
Cleared for Take Off

can you clarify what you mean here? I almost get it, but not quite.

It probably doesn't matter - I tried my supposition and it seems unfounded - it matters not if I take finger right off the shutter button (i.e. so VR stops), or leave it on, half pressed (VR continues) between successive shots. In each case, I get five RAWs before any delay is noticed, except if I am panning around between shots - then, occasionally, the AF 'loses it' and my 18-200mm goes off to one end and back again, that obviously causes a delay, but I assume that if you'd noticed that happening, coincident with the 'misfire', you'd have said.

Why not post a picture of something it happened on and save a thousand words
Despite the 'ribbing' nature of my request, that's a serious suggestion.

Cheers,

[The Stig]

Why not post a picture of something it happened on and save a thousand words

i'd like to, but the pictures won't tell us anything. Its' not the pictures, it's what happens just before the picture is taken.

Anyway, I've fired off 50+ images this evening. I've stuck to manual mode, centre-weighted metering and AF-single. I managed two shots with slight hesitation, and I think it was because of a dark subject. Granted, the focus light in the viewfinder was lit, but I think it was to be expected given what I was shooting.

I think I'll call this solved for the time being, but I'd like to be able to revisit it if it happens again. Thank you to all who spent time and effort on this, and especially Dave who went above and beyond the call of duty. Dave, what's the grand total of film rolls I owe you?

Now, get off this forum and go out and take some pictures!

Stig