is this a lens or camera body problem

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Bolerus

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Mike
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hi.

Last year I went to a radio controlled car race with a friend of mine, using a nikon D50 with a cheap 70-300 lens (one of the really cheap ones - cost me £40 from Ebay I think) and got plenty of good shots.


Yesterday i went back again with my current kit of a D70 with a sigma 70-210 APO (2.8 all the way through)

I took about 50 pictures of the cars racing, and not a single one of them is in focus, it was just incredibly slow getting focus, so slow in fact that by time it had got a focus it was out of focus again.

I also took a couple of still shots, and they are fine.

Could any body shed a bit of light, is it my lens that has a problem ( again I bought it second hand, but it was an expensive lens when it came out, but of course its probably about 10 years old now) or do I have some kind of problem with my camera?

I am at work now so I cant really do any checks, although I was thinking of taking my old cheap 70-300 lens down to the guys house and get him to race around the garden with his car or something. But could it be an option i have wrong?

I did try both single focusing mode, and continual tracking focus, didnt really see much difference between them.


thanks.
 
is this a lens or camera body problem
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I take it your not even considering a "user" problem then? if not then it's lens
 
Everything I've read about this lens comes to the same conclusion.....

..... AF is as slow as a slow thing!

I've never had so can't say :shrug:
 
kipax, i am open to all considerations.

what could I be doing wrong to constitute a user problem, taken into consideration that I did the same thing last year with a lesser camera and a much lesser lens, without the problem.

please, if you think it could be me doing something stupid, could you be more specific?

chuckles, Thanks, maybe that is the reason, would ceratinly make sense.

I (stupidly) assumed that a "fast" F2.8 would mean it was at least as fast as the cheapo lens.

Incidently in conversation with the guy I went with, i took a quick snap of him, at 2.8 just to show him how the lens throws the background out of focus, and to be honest, when I got home I was amazed with the result, it was one of those shots you sometimes take that remind you why you took up the hobby lol.
 
I think the fast with these referst to the shutter speeds you can get with the 2.8 as opposed to an f5.6 or 4.5 lens.
Done a quick google and as Chuckles says, the AF speed ( or lack thereof) seems to pop up quite a lot. If you get another chance, could you try manual focus instead?
Only thing I know about these little cars is that they're quick so panning might be a tricky thing to master, but if you pre focus on an area of track and time it right you should be OK. (I'm assuming you were using a fast shutter speed to "freeze" motion rather than capture it).
 
yeah Yobo, I did do a bit of panning in manual the last time I went, but to be perfectly honest, I was a bit pre-occupied this time with how long it was taking. did a few shots in manual focused on one area, they wernt perfect but better than the others.

luckily, they do meet every week at the track, although not usually as many racing as there are on teh actual race days, so there are options to get another crack at it.

i did at one point, use f2.8 (actually shows as f3 on my cam) and it set a 4000 shutter speed, which made me chuckle.


ah all low f number zoom lenses slow to AF or have i just bought a particulary bad one (as is my usual luck)

I was hoping to use a very low f stop to get a nice blurry background, maybe I will have to go back to cheap lens and blur in PS lol

thanks for the comments they are apreciated and haev helped to make me feel a bit better ( was starting to worry about my gear and my ability (well still worry about that, but at least there is a chance that will improve) )
 
Bolerus said:
please, if you think it could be me doing something stupid, could you be more specific?
Click to expand...


I just found it odd that you decided it was camera or lens and not you... From reading forums I have found that 90% of the time it ends up being the user.... but thats not 100% the case. In fact from what I read from other replies it could be as I also wrote... the lens :)

I was just opening the possibility.. not accusing :)
 
I have done a bit of RC togging myself and the best thing to do is focus manually on the section of the track and snap them when they come into focus.
 
the reason i asked about camera or body and not if it was me in the first instance was becasue I have done the same thing previously with a lesser set, and got good results in all but a few of the pics, eg last time I took about 100 shots and of the 100 perhaps 10 ( or maybe a few more but certainly less that a quarter of all the shots) of them were out of focus (and they were mostly ones that I had tried panning with) of the remaining 90 or so perhaps a third were thrown away because the composure side of them (if composure is the right word for a moving picture) was no good.

Then this time I took around 50 with AFon and they were all out of focus, kind of speaks for itself really, unless there was a setting that i messed up with, which would be as you rightly pointed out a user error

here are a few from last time i went. Just to note that when I took these I had had the camera for about a month, and there are things I was happy with then, that I wouldnt be now. (I dont have any of the ones I took yesterday with me, these were just on the net) The ones I took yesterday were all badly out of focus, if it helps i can post a copuple tonight maybe, but I think in reality the question has probably been answered.

oc5.jpg


OC2.jpg


DSC_0313.jpg


I chose these ones to post, not because they were the best or anything, but because they all show that there was a lot of movement and not just still shots,. if that makes sense
 
Certainly doesn't seem to be much wrong with those, and as you say you have nodoubt moved on in the meantime with technique etc.

It ceratinly sounds like your current lens is the root cause - that slow AF isn't somethign you need for this work, and you say its ok on static shots where it has time to focus correctly. You are right to try the old lens again, it should confirm the view on here
 
I have a Sigma 135-400. The reason I don't use it anymore was the really slow focus.Apart from that it was an OK lens. Opted for a Canon 100-400.

As suggested possibly the best option is not to use the AF function but to focus on a section of track and pan the subject till it gets to the focus point. Also at 2.8 you really don't have much DOF.
 
I presume you were using the continuous auto focus setting?
 
both continous and single target (flipped between them a couple of times)

Since discovered that of the 50 or i took, abtou half a dozen of them are in focus ish, but certainly not happy with them.

Any way I am confident it was a lens thing now. So I just need to look for a fast focusing lens with in my budget, and go back to the cheap and "nasty" 70-300 untill i get it, if I do these events again.

Any suggestions on a Fast focusing lens. Doesent Need to have particulary low Fnumber really, because it is usually pretty light, although fast shutter speeds are inportant
 
Something you can try is pre-focusing Find a spot on the track that the subject is going to pass through and focus on that, then switch to manual and you should hopefully get some better in-focus shots.
 
yeah i do the pre focusing bit. but the problem with method is that you can miss the action, i prefer to be flexible where i am focusing.
 
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