Recently for a 300mm f2.8 IS and am wondering what the 4 buttons on the grip above the manual focus ring are for? I don't have the manual for the lens and can't find it.
The four buttons are by default AF stop (in servo mode) and on any 1-series camera, plus on the 7D, you can customize what they do.
AF distance preset is not available on all big whites (for instance, the 400 DO doesn't have it, and I am not sure about the 300). Even if, it's not the four buttons around the barrel but rather one button, one thin white metal collar and one slider to set, execute and switch, respectively.
The "Set" button by the Image stabilizer controls has the option to remember a focus length. And then you can twist the knob above the manual focus ring to go to the set focus length.
If you've got the lens on a tripod, those pushbuttons might come handy as they are easily accessible.
However, when the lens/camera is handheld, they are awkward to actuate and practically useless to me. Granted, those who have a forward supporting lens hand-hold might be able to use the stop buttons more readily.
Similarly, I have yet to use the focus preset feature once.
PetKal wrote:
If you've got the lens on a tripod, those pushbuttons might come handy as they are easily accessible.
However, when the lens/camera is handheld, they are awkward to actuate and practically useless to me. Granted, those who have a forward supporting lens hand-hold might be able to use the stop buttons more readily.
Similarly, I have yet to use the focus preset feature once.
Interesting. Maybe we just hold the lenses differently. I use AF Stop on my DO all the time, and that lens hasn't seen a tripod like, almost ever. But like you, I never had any use for the AF preset. I hear that sports people love it, though (goalie, basket, etc).
stanj wrote:
Interesting. Maybe we just hold the lenses differently. I use AF Stop on my DO all the time, and that lens hasn't seen a tripod like, almost ever.
Well, the reason for that is that with all of my lenses I have the tripod mount foot resting on my palm while the thumb and the index finger can tweak the MF ring as required. That's a balanced position which minimizes fatigue and maximizes my hold steadiness. Therefore, from that position of my left hand I can not possibly reach the stop pushbuttons.
I also have never used them but curiosity is starting to set in. Since I can't locate my docs, could someone provide a brief set of "how to" points to utilize one of these buttons for say, presetting the focus to a specific distance. As in a goalie location for soccer?
schlotz wrote:
I also have never used them but curiosity is starting to set in. Since I can't locate my docs, could someone provide a brief set of "how to" points to utilize one of these buttons for say, presetting the focus to a specific distance. As in a goalie location for soccer?
Regards,
Matt
The four Lens AF Stop buttons on the Canon Great Whites can do any the following:
Custom Function - CF III-6
0: AF Stop (Default)
1: AF Start
2: AE Lock
3: AF Point: M->Auto / Auto->Ctr
4: One Shot or AI Servo
5: IS Start
6: Switch to registered AF point
7: Spot Focus (1D Mk IV only)
The focus preset ring and switch will do what you're asking.
Move the focus preset switch to the on or "beep" positions. Focus on the desired subject. Press the focus preset button. If the switch is set to "beep" position, the lens will "beep". When you want to return to the focus preset distance, turn the small knurled ring at the front of the lens and it will quickly return to the preset focus distance.
You press and hold the Focus-Preset button on the lens and AF your camera at a point of interest in the frame (say, point A, 40 yards away). Let go of the focus-preset button now. Your target distance(AF) is recorded( like 'M+' and "MR" buttons in a calculator :-)). Now, you can shoot something else at any distance and when you quickly want to come back to point A, you can point your camera there and just *rotate* a metal ring present near/around that button to get back AF at point A distance.
Helps when you know there's action going on at 2 simultaneous locations (different distance) and you don't want the camera's AF to slow you down while recording shots at both distance (near + far). Definitely a helpful feature when one has tele-converters behind the lens which can slow AF down significantly.
PetKal wrote:
If you've got the lens on a tripod, those pushbuttons might come handy as they are easily accessible.
However, when the lens/camera is handheld, they are awkward to actuate and practically useless to me. Granted, those who have a forward supporting lens hand-hold might be able to use the stop buttons more readily.
Similarly, I have yet to use the focus preset feature once.
That would explain why I hadn't even noticed the extra buttons on the lens until this thread. I am quite leery of pressing an unknown button when that rare GBH is a kilometer away, in case even that speck of a bird disappears from the viewfinder by the time I "undo" the damage.
stanj wrote:
The four buttons are by default AF stop (in servo mode) and on any 1-series camera, plus on the 7D, you can customize what they do.
AF distance preset is not available on all big whites (for instance, the 400 DO doesn't have it, and I am not sure about the 300). Even if, it's not the four buttons around the barrel but rather one button, one thin white metal collar and one slider to set, execute and switch, respectively.
stanj which page on the 7D instructional manual can I find this feature? I think it is neat that you can customize it.
I thought one of those (when I recently rented this lens) was for the Direct Print thingy. Didn't work, by the way. I pointed the lens at several printers at a store and pressed all buttons many times.
I pointed the lens at several printers at a store and pressed all buttons many times.