300D focussing

[HoldenMan]

On another thread I saw this from Bobby C:

"forced AI-autofocus - This is a terrible, incredibly stupid handicap for Canon to build in. It's just software, why not give Rebel users the choice of One-Shot and AI Servo focus? AI Focus is less dependable than giving the user the choice of forcing one mode or another. When I had the Rebel (returned to store, whew!), the system would often break out of one-shot when I was waiting for the right moment to arise."

Could you elaborate on the focussing modes (and their problems/shortfalls) of the 300D compared to the 10D?

I got a little confused by your comment, that's all. I'm deciding between a 300D and a 10D (being a uni student, the additional cost is likely to be the deciding factor), but if the 300D has irritating habits that may cost photo opportunities then this could also be a factor in my decision.

Additionally you mentioned the expected shutter life as about a quarter of the 10D. What happens after the
20 000 images? My understanding is that the shutter's timing starts to get slightly out, and it then requires a service (though I could be wrong on that, and how much would the service cost?)

Thanks in advance for your help

[CyberDyneSystems]

I can offer some info on the focus modes.

The 10D has three modes.

Single shot.
Ai focus
And AI Servo.

Single means just that,,... press the shutter release in halfway,. and it autofocuses,. then it will remain locked on that focus while you recompose,. wait for a key moment etc.

In AI servo the Camera CONSTANTLY autofocuses while the shutter is held at the halfway point. Any shift in composition is likely to result in numerous auto-refocuses.

AI Focus is a combination of the two,. you start in single focus mode and then the camera will automatically switch to AI servo when it thinks it is needed.

Unfotunately the Rebel D is locked into AI Focus,. and I agree that this is one of its biggest downfalls. Short of switching to full manual you have no way of getting your camera to "hold still" with the autofocus while you recompose.

[HoldenMan]

On Canon's website it says the 300D has one shot, AI servo and AI focus modes............(?)

[Jesper]

The 300D does have the three modes, but the point is that you cannot choose between them - the camera automatically chooses the mode, and sometimes it may jump into AI Servo mode even if you want it to stay in One Shot mode.

[HoldenMan]

I see what you mean now........
isn't that the same as on the 3000n (my current camerah), in regards to not being able to choose between the modes?

How much of a problem is it, really?

[Guillermo Freige]

In fact, is not such a big problem. There is workarounds for simulate single shot, or force AI servo (in some cases).
To simulate single shot, just focus, and when lock is achieved, switch to MF to keep it there. Not the best solution but if works.
To force AI servo, there is 2 ways, a good and a bad one. In fact it's the same solution, but is good or bad depending the lens :).
When the camera is AF locked, and you slightly defocus the image, tha camera turns to AI servo. If you have a FTM lens, you can do this changing the focus (go to a far distance works better to me in my tests with the 28-135 IS) This is the good way. The bad way is do the same in a non-FTM lens, as the 18-55, sligtly touching the focus ring but without actually moving the motor (because it's locked by the AF switch). The touch tends to defocus a little the lens as in the FTM case, and the camera switch most of the time to AI servo. This is the bad way because is not as reliable as the FTM alternative, and probably isn't the best for the focus mechanism in the long term.

[AliasMoze]

I always use the center focus only, because I trust myself more than the computer.

BUT if I were shooting action, I suppose I'd try out the automatic functions. The important thing, though, is that you can set the focus on just the center marker, focus lock, and recompose. This works 99% of the time. A major exception is flash photography, because the ETTL uses the focus point. In that case, you can set your focus and swich to manual for the shot.

[PacAce]

99% of the time my 10D is set to AI Focus and I've never had problems with focusing. When a subject is still the camera works in One-Shot mode. If the subject starts to move towards or away from me, the camera tracks the subject.

Even recomposing after getting a focus lock in AI Focus mode is not a problem. The camera will not refocus when you recompose. The focus stays locked unless the subject moves away or towards me.

So, the fact that the 300D defaults to AI Focus mode in the Create zone and is not changeable would not deter me from getting the 300D, that is, if I were in the market for one.

But, there is that 1% of the time when I specifically need to shot in AI Servo mode. The 300D doesn't give me that option in the Creative zone. But one can always switch to the Sports setting in the Basic mode.

And, as for the One-Shot mode, I've never encountered a situation where I specificially needed that mode.

Just my 2 cents....

[kufel]

for flash you can use flash meter lock, by pressing * you prefire the flash, it meters the light at current focus point, locks the mettering for 6 sec. then you can recompose and take the pic.

[Carbon]

PacAce wrote:
Even recomposing after getting a focus lock in AI Focus mode is not a problem. The camera will not refocus when you recompose. The focus stays locked unless the subject moves away or towards me.

Unfortunately, I find that this is not true with the Digital Rebel. If you recompose and there is an object in the focus point used that is just slightly off from the original focus point, the camera will break into AI Servo. This, put plainly, just sucks. If you recompose quickly, it usually doesn't take effect. But sometimes you're waiting for the exact right moment to capture the shot, and when the camera breaks into AI Servo and totally blows the shot, it can be something of an expensive inconvenience.

I would like to start an online petition for Canon to build the following three features into the next firmware for the Digital Rebel/300D
1. selectable One Shot, AI Focus and AI Servo in the main menu system. Obviously, they can't add the symbol to the black and white LCD, but they can add the feature and put it in the menu system.
2. optional mirror lockup. Again, somethign
3. allow people the option to use the * button for Focus Lock (Custom Function 4 for you EOS junkies).

Actually, just having #3 would help with problem #1. Who would be interested in this petition? Perhaps I'll start a new thread with this subject. Maybe Canon will add it to the firmware after the 10D is out of production so there won't be the problem of cannibalizing 10D sales with the Rebel.

I do indeed now have a 10D and a Digital Rebel (300D) as a backup since I was able to get the Rebel for under $800 with the kit lens. The Rebel is a great camera that needs just a few interface tweaks. For example, why can't I just use the left and right arrow buttons to change apertures in manual mode? Instead, I need to stretch for the AV+- button while simultaneously spinning the main dial. Seems like making both methods active would be a good compromise. Other than this and the 3 petition items, I find that the Digital Rebel actually has better focusing than my particular 10D. Less backfocus at distant focusing points has made it the body I actually carry more than the 10D.

Guillermo, thanks for the advice. Turning the focus ring does indeed kick in the AI Servo on my FT-M lenses. I always find your comments on this forum most helpful.

Now, if only there was a trick to keep it in one-shot mode :) I know, I can always turn off AF on the lens after focus is achieved, but this is really a hack.

[Guillermo Freige]

I'm starting in my camera what I call "The hidden menu/features chase" :)
Usually all electronic devices have some "hidden" button combinations or button/power up sequences, to enable extra functions or menus. I'm in the chase of such "easter eggs", if any is present, in the Rebel. The usual "one button, poweron" sequences has proven inefective, but i'll pursuit the challenge :)
I'm searching mostly for: flash exp.compensation, some level of custom functions, AE mode selection or AF mode selection. If I discover something, I'll post in the list.
Wish me luck :)

[Carbon]

Guillermo, check out the petition:

http://www.photography-on-the.net/forum/showthread.php?t=18169

[Guillermo Freige]

I've already done that :)