Message posted by Koji on May 05, 2002 at 8:59:39 PST:
I am combining and using EF70-200mm F2.8L USM and EF100-400mm F4.5-5.6L IS USM for EOS-1N and EOS-3 according to a photography situation about a film camera. I was using manual type Canon F-1, before buying these auto focus types of camera. When it is Extender made from Canon, in the case of EF1.4X (1.4 times) use, auto focus speed falls to an about half, and, as for in the case of EF2X (twice) use, auto focus speed falls to about 1/4, respectively. This figure is specified on the lens catalog of Canon. This tendency is generated also except a Canon product, although there is a difference of a grade, and it is the point which must be taken into consideration if it is going to take the good photograph of quality of image. Therefore, the way which corresponds with the focal length which the lens itself has is high [ a possibility that the good photograph of quality of image can be taken ], without a bad influence arising from the speed of an auto focus rather than expecting the effect of Extender as my individual view. About me, Extender does not use it fundamentally. About the Image Stabilizer function, about me, in almost all cases, it is made Off, and a photograph is taken. About the effect of IS at the time of photography of Aircraft, the opinion has separated also among my friends. These elements are that the photographer itself finally decides, taking various elements into consideration. Therefore, I am glad if I have you profit by what I described as a recommendation matter to the last. Koji
When it is going to photo the aircraft under flight using Extender, it is important how a photographer takes this figure into consideration.
Conversely, if the photography method which will not depend only on an auto focus if it says, but unites a focus auxiliary in an auto focus, and adjusts a focus by the manual after that is taken, I will think that the bad influence by the speed fall of the auto focus by Extender use is suppliable to some extent.
And an auto focus is used auxiliary and it is making to unite a focus in a manual focus into the basic style.
In Reply to: Re: Off Topic: Lens advice posted by gary on May 04, 2002 at 21:13:00 PST:
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