Back Button Focusing - an unexpected snag

[ajohnw]

I don't know how Dave's Canon and lens works but with my Nikon you set up bbf so you only press it once and it locks and the VR doesn't kick in again, or at least I don't hear it, (keep pressed for continuous focus) and if you also set the shutter release so the exposure locks when pressed halfway you can then expose and recompose with the shutter release but the auto focus doesn't start again, some people might find this method awkward or unnecessary but I like the complete separation and control it gives over auto focus and exposure, will it help me take better pictures, no comment

True but exposure and focus can be locked independently via the usual set up. I would normally use exposure lock on the button and focus lock on a 1/2 press plus not using continuous when this sort of thing is needed so the only advantage really is not having to specifically select continuous when it's needed.

Shooting m 4/3 has really rammed home how futile exposure lock can be. The main thing on that is being able to set compensation easily as there is a direct indication of the results before the shot is taken. Normally it's a case of getting a feel for how much compensation is likely to be needed by a particular cameras metering system and applying it.

John
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[Cliff Roamer]

True but exposure and focus can be locked independently via the usual set up. I would normally use exposure lock on the button and focus lock on a 1/2 press plus not using continuous when this sort of thing is needed so the only advantage really is not having to specifically select continuous when it's needed.

Shooting m 4/3 has really rammed home how futile exposure lock can be. The main thing on that is being able to set compensation easily as there is a direct indication of the results before the shot is taken. Normally it's a case of getting a feel for how much compensation is likely to be needed by a particular cameras metering system and applying it.

John
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Yes, of course you are right, you can do it that way. I must admit that I did jump on the bbf bandwagon without fully understanding all the possible button/shutter combinations but now that I do, I think that your set up might actually be easier (apart from having to select AF-C when needed) because it does feel more intuitive to use the 1/2 shutter press for focus also it's a bigger button and falls easier to hand than the back button does to my thumb, I'll give that a try

[Glenn NK]

However with the Tamron, it seems to shut down after a couple of seconds. The other thing about the Tamron is that the instruction leaflet indicates that after IS has been activated, it is not ready for use for about 1 sec.

As a result of this. it seems to me that to use the Tamron with BBF, you need to set your BBF and then half hold down the shutter button for at least a second before taking the shot.
Dave

I apologize for posting all the useless information about how to use the Canon 600D (now deleted).

Canon's official stand has always been that third party lenses may not function properly in all respects with Canon bodies.

It seems that in the case of this particular Tamron lens, their warnings were appropriate.

Caveat emptor still rules.

[Glenn NK]

Shooting m 4/3 has really rammed home how futile exposure lock can be. The main thing on that is being able to set compensation easily as there is a direct indication of the results before the shot is taken. Normally it's a case of getting a feel for how much compensation is likely to be needed by a particular cameras metering system and applying it.

John
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Thanks John:

In the past few days, I joined the M43 forum as I was seriously thinking about that format. At the same time, I have been edging closely to bird photography - but your comments are making me rethink the issue. The local shop brought in a couple of 70-200 f/2.8 Mark II Canon lenses for me to try with my 2.0 Extender. I'm thinking more seriously of staying with my Canon gear now thanks to your experience and that of others about the difficulties of BIF photography with M43.

Glenn

[davidedric]

+1 for staying with dslr for BIF. I have nothing like John's experience, but I also have a m4/3 and have researched extensively using it for wildlife / BIF with the conclusion that it is not there yet. I suspect in two to three years it will be.

Dave

[ajohnw]

With a bit of luck I may be able to try some BIF with the E-M1 next week. Off to Wales again but it's a much better place to shoot macro than where I am at the moment.. A lot depends on weather conditions. Last time I tried - 2 mistakes. Madly high ISO and using 600mm equivalent. The ISO might not of mattered if I had waited until they got closer. Misty air caused problems with the that long a lens. My only excuse is that I was standing in a very cold wind that even managed to give me ear ache so didn't try for long.

I always wonder what peoples hit rate is with this type of shooting. I recollect a comment from some one who sold all of their Nikon gear - hit rate using continuous more or less the same except it sometimes tracks the wrong thing. Mine was 4 complet miss focuses out of 12 shots. I have the camera set so that it wont take a shot unless focus is confirmed however it sort says to hell with this and just takes a shot eventually. Others it's hard to say, misty, very low contrast anyway and an E-M5. The E-M1 should do better. The birds were flying at rather than across me as well. No point in making life easier but I wish I had now.

I most certainly wouldn't recommend some one rushing out and buying one for BIF. On the other hand there are indications about that the AF can track even rather rapidly moving things so I will give it a try. Again though - no idea of success rate.

Oh - noticed yesterday. I used a 4/3 lens which meant the camera only used phase focusing - no clipping was shown before the shot was taken - only afterwards but at least it pops up in the viewfinder after the shot is taken.

John
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[Manfred M]

Having spent seveal months shooting with a fairly good (i.e. middle to high end Panasonic GX7) mFT camera, I have to agree with what John and others have said about birds in flight and wildlife photography in general.

Can it be done; yes. Will you have a lot more misses than with other camera types? Also a yes. The upside is that you do have the 2x multiplier effect of your lens and if one decides to shoot with an electronic shutter (in burst mode, shooting jpeg only, I can record at up to 80 frames / second). The downside is that the viewfinder can't keep up and you can create a lot of missed and out-of-focus images very, very quickly (I'll give you one guess as to how I figured that out!). The low weight of the camera and body actually work against you; as it is easier to hold a larger, heavier camera more steadily. Having optical stabilization helps, but at the long end of the 100-300mm lens you get a lot of shots of air and bits of bird. Tracking your subject hand-held is impossible. I might use it for shooting elephant though; they are a big target and they don't move all that quickly, in my experience...

If I were a birder (and I'm not) I would either get a 400mm or longer prime for my full frame DSLR or potentially look at a teleconverter to be used with my f/2.8 70-200mm lens. The mFT will be reserved for things that don't move to quickly; landscapes, buildings and people when I'm out and about. In a more controlled environment; back to the full-frame DSLR.

A mFT camera has one major thing going for it; compact size, but it really isn't a camera I would consider for serious wildlife photography or sports photography.

Will it ever become a birder's camera. Again, I suspect that won't happen in the near term. Birding requires very fast glass, and putting a $2000 lens on a $3000 camera can be justified. I really can't see; based on the market niche that mFT targets, that there will be much of a market for fast, long glass.

[ajohnw]

I've been playing with converters and found that little has changed over the years. 1.4x is likely to be ok, 2x is likely show deterioration of the image.

I see little use for continuous mode shooting without focus between shots for anything other than stationary subjects. eg tennis player serving were the focus distance remains fairly constant.. There is also usually a slower mode than the flat out jpg mode

BIF? The tiny shoot I did with the E-M5 doesn't exactly rule out the fact that it might work. Have to wait and see. There are a number of video's kicking about and shots showing that the higher end cameras can track and focus things which are moving rather quickly even in continuous mode. I posted a link - rally cars in a town, probably 30-40mp TT motor bikes, probably 100mph plus. There are others, probably less challenging. One "problem" with the E-M1 is several modes to try.. The biggest problem with birds as I see it still or in flight is being near enough to get a sensible image size. 300mm = 600mm full frame helps a bit but not as much as some might think.

In terms of keeping a lens steady for the shot I most definitely find lighter is better. The catch with sensor shift IS is that it hasn't the same degree of scope as the optical variety so when pointing etc the image will bounce around more. There is a need to accept that and relax and let the camera do it's job. Actually I had a 1.1kg lens on it a couple of days ago rather than the usual just over 0.4kg telephoto. It very definitely didn't help even though the focal length was shorter.

John
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[William W]

I learned something about Tamron Lenses.

WW