09-23-2013 03:04 PM
Do you use the 100-400mm in combination with 2x extender ? What do you think about this combination ?
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04-21-2018 12:16 PM
@GeorgeMwrote:I must be doing something wrong. I have “live view” enabled in my EOS 70D and the switch on the back of the camera is set to live view. I am using a 2x ii extender. Autofocus will not work. When I try to focus on an object, the f stop setting is flashing on the display. Any suggestions?
What shooting mode are you using. Try using M mode. How many focus points are you using? Use just the center one in the viewfinder, and then try Live View, although I do not think that will really help.
The minimum aperture is probably too high. With the adapter, you will get a minimum range of f/8-11. You say the f/stop is flashing. What value of f/stop is it displaying as it flashes?
The EF 2x models are not recommended for use with lenses with minimum apertures exceeding f/4. The extender instruction manual can tell you which combinations of lenses it is compatible with. You camera instruction manual should tell you which focus points would be available, which in this case I would expect none to be available in the viewfinder.
11-09-2019 02:01 PM
The Kenko passes through all camera commands. (focus, image stability, f/setting, and meta data. The auto focus is just about useless except in very bright conditions. I put the lens in manual focus mode but all other functions are operating properly.
11-28-2018 05:11 AM
09-23-2013 03:38 PM
I know it's tempting to go for an impressive 200 - 800 mm focal length setup, but if it didn't have its drawbacks everyone would own this combination (and Canon wouldn't be able to sell the new 200 - 400 1.4X for $10,000+).
Although they increase your focal length, extenders also 1) cut out the amount of light, 2) compromise image quality. The first point has the added complication that it can affect autofocus. All cameras have a minimum aperture size that it needs for autofocus to work, most are around f5.6, some high-end cameras go up to f8. The 2X will move up the largest aperture size of the lens two stops. So the 100 – 400 f4 – 5.6 will become a f8 – f11. Even high end cameras will probably struggle once zoomed much past 100mm.
You’re most likely not going to have auto-focus, so how do you feel about using manual focus only? The 2X will also compromise sharpness a bit, so you’ll probably have to stop down the lens quite a bit to get a result you like (plus the extender cuts out 2 stops). It’s fine if you have enough light, but it’s going to cut into your flexibility.
09-24-2013 10:37 AM - edited 08-08-2015 01:57 PM
I use the 100-400mm f4.5-5.6 a lot. It isn't that sharp of lens in the first place to cripple it in any way. So a tele adapter is out of the question, even the 1.4x.
The best it gets is to use it with a Canon7D and take advantage of the 1.6 crop factor.
Oh, and BTW, the 100-400mm is a f4.5 not a f4. Unless Canon has come out with a later version.
10-13-2017 02:59 PM
10-13-2017 03:22 PM
@Bluemoon622 wrote:
Thank you for explaining that so I can understand it. What you say makes sense. But according to some users and distributors
this camera can work with the extender and lens in autofocus, but ZI am unable to make it happen. I'll still use it on occasion anyway, but am frustrated that I can not acquire AF no matter how I set it.?
It can work with a 1.4x extender (which would take that lens to f/8 at the long end of the zoom range) ... just not with the 2x extender (which takes it to f/11 at the long end of the zoom range.)
BTW, there are even limits when using f/8... you can't just use any AF point -- it supports the center point. I think it can "borrow" the immediately adjacent points when using AF point expansion mode ... but that's it.
10-13-2017 03:25 PM
thanks again, I'll play with it....
11-24-2019 10:00 AM
I picked up the EF 100-400 f/4-5.6L just recently and I'm loving it. The thought of 2x more reach even with the aperture/light penalty is apealling. I have a 5D Mark III, but I'm not sure of its auto focusing ability cranked out to 800. Likely a stationary target and a tripod for manual focusing is the best bet at this setting.
Taken at 400mm, f/9, 1/1600 sec, iso-100
11-24-2019 10:27 AM
The shot I took was hand held, manual focus. If you engage image stability during focusing is like having it on a tripod.
11-24-2019 11:42 AM
" If you engage image stability during focusing is like having it on a tripod."
It all depends on what your standards are and what results are pleasing to you. If you are happy with that shot, great. Personally I would not be.
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