1Ds MkIII vs 1D MkIV

[M_Six]

I'm thinking about grabbing a body that will AF quickly at F8 using Canon TCs. My 6D sort of kinda focuses at F8 with my Kenko TC, but the keeper rate is minimal when it comes to any moving target. Does anyone here have experience with these two bodies in combination with a 1.4x TC III? Does the 1Ds MkIII focus as quickly and accurately as the 1D MkIV? Frame rate is not critical to me. Focus speed and accuracy are. The going rate for these bodies used is close enough to be a wash, so the real deciding factor will be IQ at F8 autofocus. Also in the mix at this price is the 5D MkIII, so comparisons to that and the other two bodies is also welcomed.

Thoughts?

[Andy Stringer]

I have the 1D Mk IV, the 1.4x TC II and the 2x TC III, which I know is not an exact match for the items in your question, but I'm satisfied with the f/8 focus speed and performance when using the 1.4x TC II with, for example, a 100-400 lens at f/5.6, or the 2x TC III with any compatible f/4 lens (but especially my new 500mm L II). If you have the 1.4 x TC III, this would certainly be better than my older version, which is good enough.

The Mk IV has more options (i.e. custom functions) for autofocus performance. The correct choice of these settings for the subject that you are shooting can make a huge difference to your keeper rate, so it's worth spending time to learn which options to use in different shooting situations.

Bear in mind that none of the 1-series options for focus point tracking of a moving subject will work at f/8 because only the centre focus point is operational. If your moving targets have a predictable motion it should be easy enough to keep your centre focus point over the subject, in which case the 1D bodies should deliver improved focus performance. If your subject's motion is less predictable, such as birds in flight, you may struggle with the constraint of a single focus point at f/8. If this is the reason for your low keeper rate, it won't improve with a more advanced body. You would probably get a higher keeper rate shoting at f/5.6 using all focus points and cropping your best efforts.

[neuroanatomist]

The 1D X does decently with an f/8 combo, although there's sometimes a tendency to hunt a bit. The center point is supplemented by the four surrounding points in a '+' configuration if you set expansion mode. Since the 5DIII has the same capability, that's the least expensive option for a new camera.

[conropl]

I probably have the least experience with a 1D... so take this as advice with limited experience.

This last weekend, I was taking pictures of birds with a 1DX, a 100-400mm L, and a 1.4X II. What I found is the 1DX would focus for most stationalry things, but when I was trying to get birds in flight (and fill the frame), the bird did not hold position long enough for me to lock in focus with the 1.4X II attached, but worked great without the 1.4X II. The bird would either get out of range, or out of frame before it ever got locked in on focus. I got frustrated with the 1.4X II and removed it.

I was trying it out on seagulls that were close by (within 10-20 ft) with water (slight chop) back ground; they were flying past as I panned; or they were hovering as they drop down for a landing... fast moving ducks were out of the question. I was in Servo mode, IS set to 2. I do not think I ever got a shot off because there was to much movement to get it to lock in. After taking off the 1.4X II, I did not have a problem.

What I am trying to get across is the focusing ability is noticeably slower, and to the point of unacceptable when you have something coming in an out of frame quickly... that is, the camera took to long to lock on focus in that situation. This was with a 1.4xII and not the III... but I do not know if the III is actually faster. I understand the version III has better IQ, but I am not sure of its ability to focus faster.

For most cases it is going to be OK, but if you are looking to get quick focus of erratic movement, you may be disappointed. The 1.4X II and 100-400mm combination is not the best, but I do not know what you would be shooting with either.

So all this depends on your usage, and I would assume it varies greatly with the lens you use as well.

[M_Six]

Shot this today with the 5D MkIII from the office and my 400 5.6 + 1.4x TC (Kenko). Despite the high contrast tree in the background, the AF locked on to the bag in an instant and tracked it right along. I have a whole series of shots. I neglected to go to AI Focus, so the focus wandered just the tiniest bit in later images. I also tracked moving people and some cars, and they all stayed nicely in focus. I'm thinking now the 5D MkIII with its accurate f8 AF may be fine for me. And as the Doc mentioned, right now it's still the least expensive option of the 3 I mentioned earlier. Of course this bag is nothing compared to a distant eagle moving quickly with trees in the background. More testing still to be done.

[Joel Eade]

I just got back from short trip to South Carolina where I was able to spend about 4 hours taking bird images using the 1DX with the version I 500mm f4L + version II 1.4 TC hand held from a boat. I was having no problems locking focus on birds in flight quickly and no problem tracking either. I was using AI Servo and central point with expansion. It was very cloudy day requiring very high ISO but still no issue focusing or tracking even across complex backgrounds. I do have the focus function assigned to a button on the back so I can focus with my thumb and actuate the shutter with my index finger. I find it much easier to track objects this way. I realize this is not using AF at f/8 but using the back button for focus may be helpful as I have done the same thing using the 2 X TC version III and although it is slower the keeper rate is higher than when trying to keep a moving object in focus by using the half shutter press.