EM1 2 poor results.

Started 2 months ago | Discussions thread
Messier Object Veteran Member • Posts: 8,093
Re: AF distractions outside the box
1

RDLBlack wrote:

Messier Object wrote:

JaKing wrote:

Messier Object wrote:

Yes, but what colour is your dog, at what range and with what foreground and background distractions at the edge of the AF Target box

The cat is a blue-cream tortoiseshell Burmese. Background differed from shot to shot. Sometimes included small side table leg, off axis (deliberately). Carpet is much the same contrast/reflectivity as the cat. Range was about 1.5-2m.

I deliberately tried to confuse the AF, without success, including moving off target, focusing, then re-focusing back on target. I have experimented with this dozens of times, Peter, and cannot replicate your results, specially not since f/w 2.0. I have used all sorts of targets, mainly at short to medium ranges, but some at 15+ metres.

I will not post any here, as that would simply provide my 'fan club' with ammunition.

it doesn’t happen all of the time, but there are some subjects in some circumstances the camera has trouble.

Occasionally, all of my cameras and lenses will miss focus. I usually watch for this when I think it might happen. Using film for about 50 years was a great teacher ...

I suggest that OLYMPUS could tell you exactly the circumstances in which the camera’s AF has trouble,

I agree, Olympus should provide a very detailed printed manual. About twice as long as the current PDF one ...

but then they’d be depriving the users of the joy of discovering these things for ourselves - the OP reported a 90% failure rate with the rabbit.

I have my own thoughts on that failure rate ...

Peter

look at that 2nd image of the rabbit and tell me where you think the Single Small AF Point was positioned. By my reckoning it was fair and square on the rabbit’s eye, and look what the camera focused on, the background.

Telling us about your success with your cat does not explain these rabbit shots. Indeed, many of us could post similar success stories telling of how well the AF system does precisely pick out the desired target, but that in no way helps us understand how and why it can also fail inexplicably for some targets in some situations where we would and should expect excellent results.

Peter

The 300mm F4.0 with the 1.4x TC has a lot of reach and because of this camera movement when handholding even if the user don't notice it is enough that the small AF box can move off the small target (rabbit eye) and on to something like the grass behind it. Too better see this handholding camera movement I suggest using the 14x enlarge AF view when handholding with 420mm of reach. The 14x enlarge view is as near to the small AF box that you can get. I was surprised at this movement and this got me thinking the miss focus issues that I have had with the 300mm with the 1.4x TC might be because of movement of the small AF box off of the small target when engaging the AF. I might be wrong but so far this has been my conclusion. I did fine using enlarge AF view nails the AF and I also found that if I look to see if the subject is in focus or not haver engaging AF and if not a bump in AF will then nail it.

If this were the case then the AF Target Point would be moving onto the desired target at least as often as it moves off the desired target and at worse the OP would see a 50% fail rate.

And how with IBIS and OIS working together is there is so much Camera movement as to cause the OP to be unable to hold the AF Target point on the subject.

If the camera requires the user to engage a magnified viewing mode in order to lock focus on such an easy target then what can we conclude about the precision of the AF system ?

Peter

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