One of the main reasons I switched to Nikon was its supposedly fantastic flash system. Well, the system sucks. The AF assist beam performance is abysmal, and I think that the fix floating around the forums of turning on the assist beam off on my new $550 flash is absurd. The whole point of an AF assist beam is to outperform the on camera AF assist lamp. The Canon 580EX II flashes kick serious ass in this department, and the 600EX RT flashes, for $25 more than this crappy SB910, are the best deal out there.
Check this series of images. They are shot with the d700 + 85 1.8G, f1.8, iso 1600, 1/200th, 85mm 1.8 G. The only thing I did was turn the AF assist beam on and off on the flash. I used the top left, top center, and top right AF points. In all cases, the AF assist beam caused the flash to back focus about an inch. This makes the flash gun unusable for its intended performance.
NIKON: GET IT TOGETHER. THIS IS TOTALLY UNACCEPTABLE.
bummer to hear about your experience. i switched to nikon and for what i shoot i find the exact opposite to be true. IMO, the flash metering and the whole flash system is much better than canon.
i often struggled getting it right with canon but not so much with nikon.
Grantland wrote:
bummer to hear about your experience. i switched to nikon and for what i shoot i find the exact opposite to be true. IMO, the flash metering and the whole flash system is much better than canon.
i often struggled getting it right with canon but not so much with nikon.
The exposures are spot on, which is great, but in super dark rooms where people are moving around quickly, AF-C doesn't cut it and the on-camera AF beam isn't powerful enough.
The new Canon system allows each channel to have a run in a different mode, so you can have your rim lights set in M and your on camera bouncing off the ceiling in TTL. This was only possible on Nikon when I switched, but not any longer.
i find it hard to believe you went to Nikon for the flash system as a primary reasoning that would have been silly. i suggest you learn how to shoot the camera system as i had to when i used Canon.
Do you have any micro adjustment set for the 85mm? I found that my focus was spot when using my flash at F1.4 compared to being out of focus without the flash. Maybe switch it to 0 micro adjustment to see how it goes.
nswelton wrote:
Please fill me in on how I can use my camera system better. If I can get images that are in focus with the 910's AF assist beam I'll be stoked.
do you know how to light a scene or a situation or are you trying to rely on the systems automation to do the work?
do you know how to use the various AF metering patterns in your camera for various focus situations/issues?
do/did you practice using the sytem before going into the field/job with it?
Same problem here. I know it is not ideal, but you might try to turn off assist light of the flash, but enable the built-in flashes assist light. That might work better (never tried it myself though).
I hope this gets fixed with a firmware update soon - it is very annoying.
Very happy with the 85 -- it's insanely sharp wide open, moreso at 1.8 than my old 85L II was. So no micro adjust needed.
The back focus also occurs on the 35 1.4 and the 50 1.4. It's a lot better on the 24-70G but still not totally reliable.
Your experience has been the opposite?
Perplexing!
MikeW wrote:
have you tried it on a different lens?
Do you have any micro adjustment set for the 85mm? I found that my focus was spot when using my flash at F1.4 compared to being out of focus without the flash. Maybe switch it to 0 micro adjustment to see how it goes.
I am experiencing this as well. Apart from what is mentioned above you can shoot with older flash units like the SB 800 or SB 600. It's the newer generation of flashes such as the sb900, sb700 and sb910 that exhibits this behaviour.
the only connection between the camera and focus is the projected pattern there is no other force involved. if it focuses normally w/o it you need to think of the AF pattern you are using and what other elements of it are reading what and where in the image in addition to the focus pattern. understanding the individual patterns is important. it will tend towards the contrastiest and easiest to read object in the image.
Happens to me as well (D3s, SB900, various primes)... interestingly, a series of experiments revealed that it occurs even if the assist beam is BLOCKED (in other words, it's not that the AF system is somehow confused by the projected pattern on the subject). This indicates it's a firmware bug, presumably the result of some alternative (but incorrect) focus routine being employed when the AF assist beam is active on newer speedlights.
My own theory: Others have observed that the color temp of the ambient light (and the color of the subject as well) can cause front or back focus. Since the AF assist beam is red, perhaps Nikon engineers added a provision to the firmware to preemptively try to counteract a presumed focus shift (resulting from the red beam) by automatically shifting focus in the other direction by a guestimated amount.
But it's not working out very well.
What I end up having to do is keep the AF assist off most of the time, but when a situation arises that requires its use, I have to remember to go into the AF micro adjust settings and dial in an appropriate adjustment. It's a crappy workaround... Nikon needs to fix this.
I've tried. One problem is that there is seemingly no true equivalent to CPS. With Canon, I could call and immediately speak with a knowledgeable DSLR tech. With Nikon, I get, "Press 1 for Coolpix cameras, press 2 for slide scanners, press 3 for binoculars", etc. When I did eventually get to speak with someone, I sent in a complete kit (D3s, 50 1.4, SB900) that clearly exhibited this problem. It came back pronounced "fixed", but was still doing the same thing. I contacted the tech again, and he said he would investigate further with in-house gear. I never heard back from him, despite several followup inquiries. That was a few years ago.
In April, I decided to try emailing NPS, describing the problem. They responded that someone from "Service Relations" would get back to me. Haven't heard anything from them since.
I am now a Canon shooter because of this. Twin 5d3s and a quartet of 600EX-RT strobes. No problems whatsoever. Took about a week and I came out a few hundred bucks ahead.
