It only became possible to "set" the focal length in the camera after SR
was implemented, Prior to that I don't think that Pentax or anyone else
bothered since that was unimportant to the cameras ability to use the
lens and being able to arbitrarily change the focal length in the EXIF
could lead to unverified data being stored. Let's face it knowing the
focal length doesn't change the exposure decisions the camera has to make.
On 8/17/2018 1:19 AM, Subash Jeyan wrote:
i had the 1.7x AF TC long back (used with the A*300/4) but as far as i
remember there was no way to set the focal length manually in the body. of
course i may remember wrong....
On Fri, Aug 17, 2018 at 9:55 AM Alan C <c...@lantic.net> wrote:
That is a very interesting point. I'll try setting the focal length
manually using the 1.7x AF converter to see if there is any improvement.
Alan C
On 16-Aug-18 08:28 PM, Mark C wrote:
If you have both you can test them out. My experience has been that
unless the teleconverter and lens are designed to be used together,
results can be unpredictable. Sometimes great, sometimes not.
If you are planning on using the setup with shake reduction enabled,
check to see of the TC sends adjusted focal length info to the camera,
or if just passes through the the lens focal length. I think that for
image stabilization to work optimally the camera should be set to the
adjusted focal length (lens focal length X teleconverter power), so
you may nee to manually set it.
Mark
On 8/15/2018 11:02 PM, Subash Jeyan wrote:
i'm going on a winter trek to the himalayas in november. planning to do
some birding also along the way and since the sigma 150-500, at almost
2kg, is too heavy for that i was looking at alternatives.
i have a tamron 1.4x pz-af (af works with sdm too) and i was wondering
if i could use that with the da 55-300. i did some googling and the
results surprised me. it looks, in spite of all the conventional wisdom
that TCs can only be used with a sharp prime lens, people have got good
results. see the (old) thread here:
https://www.dpreview.com/forums/thread/3680410
have any of you used 55-300, or any other zoom, with a tc? if so i'll be
interested in how that went...
thanks, subash
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