Sigma 120-400 apo dg hsm os
PS: have you used it with the Kenko PZ T/C?
K-3 II, K-3 and a K-70 from SRS

Hope that helps
k5iis k200d
8mm fisheye sigma 15mm sigma 10-20 3,5 hsm
tamron 17-50 2.8 pentax 18-55 al ii sigma 18-125 hsm tokina 28-70 atx pro ii pentax F 35-105 pentax A 50 1;1;7 pentax 55-300 sigma 70-200 apo ex 2.8
kenko pz af 1.5 tele tamron pz af 2.0 tele and a flash
Will post photos later this week as I am away from home and yes used it with a 1.5 pz and result were OK used it with a 2.o and would not lock on kept hunting
Hope that helps
Thanks and my experience with the Sigma 100-300 F4 and Sigma 2.0 TC was similar at times.
Will be interested to see some shots!
K-3 II, K-3 and a K-70 from SRS

k5iis k200d
8mm fisheye sigma 15mm sigma 10-20 3,5 hsm
tamron 17-50 2.8 pentax 18-55 al ii sigma 18-125 hsm tokina 28-70 atx pro ii pentax F 35-105 pentax A 50 1;1;7 pentax 55-300 sigma 70-200 apo ex 2.8
kenko pz af 1.5 tele tamron pz af 2.0 tele and a flash
Home on Friday if you can wait it'll post photos with the 1.5 for you to look at
No problem!
K-3 II, K-3 and a K-70 from SRS

Z-1p, K-1, P50
F50 1.7. FAs 24, 35, 50 1.4, 85, 135

Metz 45 CL-4, AF500FTZ. AF540FGZ.
Some Mamiya and some Nikon
Depending on which camera model you have getting reliable AF at f8 would be a huge ask... even with f8-compatible Nikons (D500, D850, D5/6) AF performance is limited at f8, possible at f11 but only just.
Actually, having bought and then sold (it's now in Russia!) a 150-500 DG OS HSM because of the relatively slow AF compared with the 100-300 F4 (mainly because of the former's much longer focus travel), my biggest concern is the AF speed.
NB: that was/would be when using it with a K-3/K-3 II which have much stronger focus motors than the earlier Pentax DSLRs.
By comparison, using any TC with with the 120-400 is a much lesser one!
PS: As well as the slow focusing, that 150-500 didn't seem very sharp or contrasty, even when it had achieved good focus lock, and so that was the other reason I sold it.
K-3 II, K-3 and a K-70 from SRS

Actually, having bought and then sold (it's now in Russia!) a 150-500 DG OS HSM because of the relatively slow AF compared with the 100-300 F4 (mainly because of the former's much longer focus travel), my biggest concern is the AF speed.
NB: that was/would be when using it with a K-3/K-3 II which have much stronger focus motors than the earlier Pentax DSLRs. [quote]
... Bump to ask if anyone can comment on the length of the focus travel (i.e. how far do you or the motor have to turn the focusing mechanishm in the barrel to focus the lens from/to closest focus to/from infinity) ?
K-3 II, K-3 and a K-70 from SRS

Really annoyed me at the time as my Sigma 70-200mm OS HSM started mis focusing straight after the firmware update as did a couple of other HSM lenses I had.
Could have been just my experience though.
. My Flickr
I am pretty sure that from the K-3 (or maybe it was the K-3II) Pentax bodies stopped working with Sigma HSM lenses correctly when using a teleconverter with SDM contacts. From what I remember it was when Ricoh bought out the Pentax 1.4x, they released a firmware that supposedly fixed an "issue" with SDM but in the process it stopped the Pentax converter working with Sigma HSM lenses. I always thought it was to stop us using the new 1.4x with Sigma HSM and In the process it also stopped the Kenko and Teleplus converters that had the SDM contacts from working with Sigma lenses as well.
Really annoyed me at the time as my Sigma 70-200mm OS HSM started mis focusing straight after the firmware update as did a couple of other HSM lenses I had.
Could have been just my experience though.
Mike
My 3 pennath on the above : Before I sold the 150-500 HSM in early 2018, I found I could use my Kenko 1.4x pz tc with that lens on the K-3 II and it would still autofocus but VERY slowly (the lens had been checked out by Sigma Imaging in 2015 because I thought it focused very "slowly" - but apparently that was normal for that lens!

Therefore, if there was that sort of f/w update then I presume it happened after about mid-2018 as I always updated the camera f/w as soon as possible after it was released.
K-3 II, K-3 and a K-70 from SRS

. My Flickr

120mm 1/2000 f8.0

400mm 1/2000 f.8.0

400mm 1/2000 f5.6

120mm 1/2000 ff5.6

400 1/2000 f5




k5iis k200d
8mm fisheye sigma 15mm sigma 10-20 3,5 hsm
tamron 17-50 2.8 pentax 18-55 al ii sigma 18-125 hsm tokina 28-70 atx pro ii pentax F 35-105 pentax A 50 1;1;7 pentax 55-300 sigma 70-200 apo ex 2.8
kenko pz af 1.5 tele tamron pz af 2.0 tele and a flash
All the gear with no idea
reso
Member
worcestershire
Would trade for a pentax da 15 or 35 Ltd
k5iis k200d
8mm fisheye sigma 15mm sigma 10-20 3,5 hsm
tamron 17-50 2.8 pentax 18-55 al ii sigma 18-125 hsm tokina 28-70 atx pro ii pentax F 35-105 pentax A 50 1;1;7 pentax 55-300 sigma 70-200 apo ex 2.8
kenko pz af 1.5 tele tamron pz af 2.0 tele and a flash