Advice please :)
I use a Pentax K-5IIs, a K-3II and a 7D (MKI)
The AF speed (especially the tracking) is generations behind Canon and Nikon so if this is a priority I would perhaps look elsewhere unless you are prepared to work harder to get what you want. I'm not saying it's impossible to shoot fast flying aircraft, I do a lot of airshows and take both my Pentax and Canon cameras but you have to be prepared to trawl through a lot more OOF shots with the Pentax gear to find the ones that are acceptably sharp whereas with the Canon there is a much better hit rate.
Also remember the fps on the K-1 is pretty slow compared to the MKIII so when you team that up with the average (at best) tracking ability I would imagine it could be a bit frustrating.. There is someone on here that recently posted some photos from the Welsh hills of low flying aircraft which were pretty good but again I don't know what his hit rate was like.
Saying that, I much prefer that one shot taken with the Pentax over the many from the Canon, it's a strange thing that although I have just basically trashed Pentax gear I will always pick it over the Canon when going out 99% of the time.

Macro, wildlife etc (not BIF which is much the same as fast aircraft in my experience) are much the same from both makes although you won't get anything like the MP-E65 (the reason I first bought a Canon) for Pentax
. My Flickr

I have never found the AF system of any modern DSLR to be a problem. The CSCs can be very slow by comparison. But as with all things, we can work around them and the overall benefits can outweigh having to take more care with one aspect of a camera's performance.
Best regards, John
Decent fast shots can be had with Pentax kit and the K1, I agree with Mike P that both Canon and Nikon have a higher keeper rate, but I take a different approach and don't " machine gun " a subject and get 20 shots of the same subject and delete 18 of them, When shooting alongside our Canikon colleagues, they do seem to just keep their fingers on the " Go " button
I take my time and shoot say just 4 and ensure the technique is good. below are 3 recent images with a K1, with old-ish sigma lenses, all seen on here before.



Other Pentax ( PU ) users, will have similar and better images than mine.
Chris
www.chrismillsphotography.co.uk
" A Hangover is something that occupies the Head you neglected to use the night before".
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K1 - Sigma 85mm F1.4, Pentax DFA 150 -450 F4.5 / 5.6, Pentax DFA* 24 - 70 F2.8
Samyang 14mm F2.8, Pentax DFA* 70-200 F2.8
K3iii + K3ii + K5iis converted to IR, Sigma 17 - 70 F2.8, Pentax 55 - 300 F4.5 / F5.6 PLM



My first attempts were not very successful but I found not using the 'machine gun' technique improved thing considerably.
I agree with Chris........It comes down to technique. After all, people were able to capture birds in flight using manual focus! I've sat next to Canon users in a bird hide while they were 'machine gunning' away at a kingfisher sitting on a perch!

Regards,
Michael
My new website:link

I take my time and shoot say just 4 and ensure the technique is good.
This statement sums up Pentax experience rather well. More respect for gear and more consciousness while shooting. Can't be bad.
No reason not to get reasonable bird in flight photos with a Pentax

K-5 with Sigma 150-500 @ 400mm 1/1250" @ f/6.3 ISO640 Bempton Cliffs, East Yorks.
John K
I shoot with a K5iis, K1 and Nikon D7000 (came out same time as K5 from memory)
I gave up bothering using Pentax AFC a long while ago and have more success using centre point AF point.
I do shoot most of my motorsport with Pentax, but even in motorsport its relatively easier to pick spots to take pictures, and panning doesn't cause too much of a problem (high F stop normally adds to depth of field so I guess that helps.). Where the pentax lets you down is the more spontaneous shot when say a car spins off and you want to catch a number of shots straight away and the hit rate is not good. I don't think the Pentax autofocus systems in the lenses are quick enough which is the main problem.
TAV is not unique, its just called manual with auto ISO on Nikon and works exactly the same. I use this on my D7000 for running events with AFC and runners coming towards you - far more keepers than pentax AFC.
I prefer the Pentax cameras, and I know people say that technique can help (I know) but with current technology the Pentax AFC should be better.
Regards
George
You have no name, ..
You've just signed "Stephen" as you could have signed "Sandy" or anything else.
Are you a photographer or just a gadget man ?
Let's suppose you're sincere, .. any chance to know why are you leaving EOS ? .. Honestly, I don't care your answer, but be sure you've got a serious one, ..
...

senn
my flickr gallery
my PPG
Other half uses Canon, I use Pentax and Nikon. Having grown up with Pentax, it's a system I am familiar with and acknowledge some of the limitations (flash and AF being one) - when I chose a Full-frame I chose a D3 as I thought the menu systems were not too dissimilar to the K20D I had then. Today the D3 is sold to pay for the K-1. I look at my partner's 5D2 and 7D2 and completely baffled with the menu system and ergonomics. So coming in the other direction you will probably have the same.
Why have you got rid of the EOS system? and the 5D3? Weight? Cost? Or some aspect of the EOS system that you are not comfortable with? Or have you been seduced by some of the lovely prime lenses Pentax makes?
I am like Mike-P (Mike might disagree/baulk) 2 systems is like having 2 cars one for work and 1 for pleasure, when you walk away from the 'pleasure' one you always just turn to have another glance....that's the car version of the Pentax.
Welcome!
Peter
AKA Welshwizard/PWynneJ
Assorted Pentax/Nikon/Mamiya stuff

I think what's good, around here for us, is how the K1 plus recent lens developments have legitimised these discussions ..... They used to be uncomfortable comparisons (when we're not supposed to discuss competing brands), but the K1 has made it easier, and clearly drawn in new people with a new interest in Pentax.
So we don't need to defend things much now I feel ... The pros and cons of each full frame system and the camera models are laid out more clearly for all to see now, in the general photography press as well as in online reviews and forums. The K1 continues to punch well above it price weight, It's a great value choice with a large number of special features and the highest image quality in the class.
We've had recent discussions here with a guy trying to get decent BIF shots with the most budget Pentax choices, and he's come on with it quite well just with technical practice. The same applies at the high end as well, and it's all about knowing your camera and working with it. I feel it's that aspect that will ultimately produce the results rather than technology differences between brands.
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver

John K
Steppy
Member
I have just had to sell my Eos setup, i had a 5D mark iii, and now i'm not tied to a system i'm thinking the K1 looks a nice piece of kit, maybe for Christmas. So i am asking Eos users or ex-Eos users how they get on with the Pentax system in comparison.
My photography consists of many aspects. I love macro,i also shoot jets at low level in Wales. I also like light painting , wildlife/zoo photography, & have done a couple of weddings.
I love full frame and the extra dynamic range it offers.
One of my main concerns is the focusing speed & tracking of the Pentax system & if it's up to the job of tracking the jets. 4fps doesn't bother me.
If the are any Pentax users that do the jet thing, or shoot fast paced stuff like motorsports then please have your say.
Thanks in advance . Stephen