A question for Canon 7D owners (mainly)
Discussion
Further to my previous thoughts:
Having now assessed a lot more of the day's take AND finally got around to looking at the shots from my 400D I am somewhat puzzled.
The first thing I'll mention is that the extra resolution combined with the 70-200 f2.8 Mk2 is superb.
With my 70-300 DO - which is recognised as a very sharp lens in most tests - is also excellent. When it focuses.
The 400D can struggle with focus, especially niciable for action shots, with a lens that cannot go wider than f5.6. I have recognised this with the 70-300 sometimes when at the 300 zoom end where it only claims to offer f5.6, noticably even when the centre focus point on dark, low contrast subjects. Also when shooting continuously there will often be a shot in the sequence, usually the second or third, where it is very clearly out of focus. The common factor seems to be the influence of the centre of the image. It's most evident on pan shots, as one might expect since the focus point contrast level could vary a lot. However I recently had the use of a lens with max f6.3 at the longer end and that offered softness on static subjects at a relatively high shutter speed but nearly always when contrast in the focus area was lacking and especially when the subject was a dark colour.
So - one should expcet some limitations, there are some and I am familiar with them.
What surprises me a little is that the 7D seems rather prone to the same limitation - perhaps even more than the 400D, though to be honest that impression is probably based on the number of frames assessed and of course since the sensitive shutter buttons on the 7D will, in high speed continuous mode, rattle off a couple or three shots when it feels you shutter finger approaching, the sheer volume is not a reliable measure!
Now it may be that the 70-300 DO is simply too slow at AIServo focusing .... but then it seems to me to be fine as long as it is not at its 300mm extent. As soon as it falls into a focal length that has wider than f5.6 available the results are much more reliable. (I assumed this was all down to me but the same results can be seen across a range of shutter speeds which pretty much eliminates camera movement as the oonly cause. There are good and less good results at all shutter speeds - the focal length seems to be the most cnsistent factor.)
Is anyone else seeing the same thing or am I barking up the wrong tree?
I've re-checked the various settings available for focus use and there are a couple of experiments I can try - including simply selecting a single point (as with the 400D). I was using AF point expansion since that seemed to offer some potential benefits yet still be working only on the subject rather than its surrounding. As I mentioned everything seems within expectations, for the most part, at anything less than 300mm.
The potentially interesting thing about all of this is that the recently announced 70-300 L spec lens is f4-f5.6. (The DO is f4.5 - 5.6). So is there some chance that the new lens might see the same issues? Or do I need to get the DO serviced?
Clearly this is not just a case of spending the money - at least not on the body front.
The implication would seem to be that only the fastest lenses make sense (though I have a a handful of shots taken with a borrowed 70-200 f4 +1.4 extender. That combination seemed to be fine, though not as sharp as the f2.8 Mk2.
Having now assessed a lot more of the day's take AND finally got around to looking at the shots from my 400D I am somewhat puzzled.
The first thing I'll mention is that the extra resolution combined with the 70-200 f2.8 Mk2 is superb.
With my 70-300 DO - which is recognised as a very sharp lens in most tests - is also excellent. When it focuses.
The 400D can struggle with focus, especially niciable for action shots, with a lens that cannot go wider than f5.6. I have recognised this with the 70-300 sometimes when at the 300 zoom end where it only claims to offer f5.6, noticably even when the centre focus point on dark, low contrast subjects. Also when shooting continuously there will often be a shot in the sequence, usually the second or third, where it is very clearly out of focus. The common factor seems to be the influence of the centre of the image. It's most evident on pan shots, as one might expect since the focus point contrast level could vary a lot. However I recently had the use of a lens with max f6.3 at the longer end and that offered softness on static subjects at a relatively high shutter speed but nearly always when contrast in the focus area was lacking and especially when the subject was a dark colour.
So - one should expcet some limitations, there are some and I am familiar with them.
What surprises me a little is that the 7D seems rather prone to the same limitation - perhaps even more than the 400D, though to be honest that impression is probably based on the number of frames assessed and of course since the sensitive shutter buttons on the 7D will, in high speed continuous mode, rattle off a couple or three shots when it feels you shutter finger approaching, the sheer volume is not a reliable measure!
Now it may be that the 70-300 DO is simply too slow at AIServo focusing .... but then it seems to me to be fine as long as it is not at its 300mm extent. As soon as it falls into a focal length that has wider than f5.6 available the results are much more reliable. (I assumed this was all down to me but the same results can be seen across a range of shutter speeds which pretty much eliminates camera movement as the oonly cause. There are good and less good results at all shutter speeds - the focal length seems to be the most cnsistent factor.)
Is anyone else seeing the same thing or am I barking up the wrong tree?
I've re-checked the various settings available for focus use and there are a couple of experiments I can try - including simply selecting a single point (as with the 400D). I was using AF point expansion since that seemed to offer some potential benefits yet still be working only on the subject rather than its surrounding. As I mentioned everything seems within expectations, for the most part, at anything less than 300mm.
The potentially interesting thing about all of this is that the recently announced 70-300 L spec lens is f4-f5.6. (The DO is f4.5 - 5.6). So is there some chance that the new lens might see the same issues? Or do I need to get the DO serviced?
Clearly this is not just a case of spending the money - at least not on the body front.
The implication would seem to be that only the fastest lenses make sense (though I have a a handful of shots taken with a borrowed 70-200 f4 +1.4 extender. That combination seemed to be fine, though not as sharp as the f2.8 Mk2.
S47 said:
Your 7D deserves better glass than the 70-300, you have to accept that fact and live with it, why do you think canon have just released a MK2 version of 70-200 IS 'L' F2.8 [and several other lenses for that matter] - simply becaiuse the old lenses are not up to resolving what a 7D body [or a 5dmk2 for that matter can] your 70-300 is not in the same league aa a 'L' series lens so work it out for yourself 
Hmm.It is the DO version of the lens, not the cooking consumer version, and as such is marketed and priced by Canon in the L spec class along with its 400mm DO sibling. They are not given the L spec red ring identifier - because they have the DO spec green ring version.
For what it's worth the results, when correctly focused, from my DO lens are at least on a par with the 70-200 f4 +1.4 extender for sharpness. The chap using that was working with, iirc, a 1D4. The results looked excellent on screen - but then so did all all of them. I only took a few shots with that combination and it would be difficult to be certain that focus was always accurate based on those.
That said you make a good point - Canon have upped the quality of the 70-200 f2.8 with the Mk2. Presumably they will be doing the same with the other popular lenses - 100-400 for example, and we should assume at this point that they have already addressed this with the recently announced 70-300L lens. Excellent. But that means that to buy a £1k body and make it usable you also need to spend about £6k on lenses (making some assumptions about the likelihood of future prices doubling compared to exisiting lenses - as happened with the 70-200 f2.8) IS it worth it?
If you go back to the start of the thread you will find one of my main questions was about whether the 18Mp sensor/latest quality 70-200 Mk2 lens was indeed good enough to avoid the need and cost of having something longer as well - so as you can see I am already aware of the argument that the new high resolution sensors demand (or even require) 'better' glass.
More to the point, in relation to what I posted that prompted this response from you, will they focus consistently on a 7D at f5.6? As far as I can guess there is no guarantee that spending the cash resolves the focus question with any certainty. Not sure a 100-400 f2.8 would be affordable or indeed usable. This is a focus question NOT a resolution question.
Or have I just got an unfortunate combination of body and lens or not found the settings that work best? Any observations about what focus settings seem to work well for moving subjects would be welcome - I'll try them out.
MonkeyHanger said:
LongQ said:
Any observations about what focus settings seem to work well for moving subjects would be welcome - I'll try them out.
This is the post i made on another Photography Forum after my first shoot with the 7D last October. I'd been out of action over a month with a Torn Bicep so i'd had plenty of time to read the Manual and set it up as near as possible to my 1DMKIIN. These are the AF settings i used for the majority of the day...some fine tuning/experimenting is still to be done.
CFn III.
1 Between 0 and Slow. I found slower is better...
2 0 : AF Priority.Tracking Priority
3 1 :Continuous AF Track priority
4 1 :Focus Search Off
5: 0 : Disable
6: Single point, Spot AF and Zone AF enabled.
7 0: Stops at AF area edges (i found Continuous to be rubbish from a quick try)
8 0:Auto
9 1: Enable
10 : 0 Enable
11 1: Disable
12 0 : Same for horiz/vertical
Hope that helps
Just checked. Much the same except for
1. Set to 0 at the moment. I'll experiment with slower.
4. Focus search ON. Not sure what the effect will be under good conditions.
5. Adjust by lens - though I'm not sure this matters at all and it was only set for one lens.
6. I have a few more registered but that is not material for the actusal shots afaik.
9. Disabled - but again not an issue for image quality afaik.
Playing with the 70-300 DO today and I realised that at up to 200mm it is as sharp as anything (almost) but somewhere between 200 and 300 it goes a bit soft UNLESS focussed at infinity (or maybe close to infinity) when it seems to be sharp again. It's due a service anyway so I'll ask them to check it over. However it certainl makes for confusion when just looking at results in the absence of all the shooting information.
Also, shooting a sequence of the same stationary target the focus is not quite the same for each shot - notably the first looks better than the second. This is much more obvious when pixel peeping at the higher resolution of the 7D compared to the 400D.
I also suspect that one loses a tad of sharpness with IS - but on balance better to have it than not.
Thanks again.
Edited by LongQ on Thursday 2nd September 17:39
RobDickinson said:
If your shooting a stationary target then AI Servo is the wrong mode, pretty simple.. AI servo is expecting a moving target and trying to predict where it will move too.
That's a fair comment Rob but I can't see people chopping and changing their focus mode second by second at, say, a sports event. My guess is that they set up (as I do) for mainly moving subjects and then leave it like that most of the time. Or maybe use the To be honest I have not really considered what that effective differences would be in practical use, other then the potential for unwanted re-focusing on a stationary subject (or something that appeared to be stationary to the camera's systems) and additional battery drain. Maybe responsiveness as well. In fact the main reason, in AF terms, for using One Shot AF seems t be the ability to pre-ocus and then move to different framing, suggesting that the servo mode is the main AF system design objective. That in turn suggests there is nothing much to be lost by using AF servo all the time, given a fast focusing system and a responsive lens.
I don't think the checks I ran today would have been influenced much, if at all, by the mode since they seemed to be consistent with the results on the day.
A quick re-check this evening clearly showed the 70-300 DO being sharp enough at 200mm but much less so just past that on its way to 300mm. If the light is good tommorrow I'll check at different apertures but, from memory, the shots from Monday already offer the evidence for the softness at different apertures.
I have a 70-200 f2.8 Mk 2 to play with for the weekend.
And a 14mm f2.8 L.
Thought I might as well go for it whilst some opportunities for interesting pics have arisen suddenly.
M-J-B said:
Good thread and sorry to change the subject, but I've pushed the button and gone for a 5D MKII....
I think the 2 cameras are entirely complementary from what I can gather talking to a few people who have access to, and use, both. In fact I was chatting to a chap at the weekend who was carrying a 7D, 5D2 and 1D4, each with different lens categories fitted in order to be ready for whatever came into view. Given the amount of long L glass in view I was impressed with his strength, stamina and bank balance! Nice guy too. If I could justify it I think I would be tempted to have both bodies for shooting varied subject matter.
Well, I'm still processing the stuff I took with the 7D and I have to say that it is impressive - ridiculously so with a 70-200 f2.8 Mk2 attached.
However I have been lucky enough to pick up a very nice lightly used 1D Mk3 so the 7D may need to wait a while. The saving on the memory card budget should allow me expand the L spec lens collection quite considerably.
If anyone has a spare 24-105 I could be interested.
However I have been lucky enough to pick up a very nice lightly used 1D Mk3 so the 7D may need to wait a while. The saving on the memory card budget should allow me expand the L spec lens collection quite considerably.
If anyone has a spare 24-105 I could be interested.
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