[UserAccessDenied]

My Tamron 300 2.8 with the 1.4 gives me 420 ƒ4. Sigma also make 300 2.8., and I believe they have a 2x for theirs.
The Tammy with the 1.7 gives me 510 4.5... an A*300 2.8 with the F 1.7x AF Adapter also gives you 510 with limited AF. On the K-3 thats almost an 800mm FoV and still not 5.6. There are just to many cheaper ways to get there.

Had to read that a few times; do it fast and out loud and people will start to stare...

I do think I would benefit from a 300mm f2.8 and a 1.7/1.4 tc...
Though, it would be nearly impossible to get rid of my DA*300. I just love that lens.
Unless there was a DA*400 - I know it's unrealistic, but I can dream a bit.

I wish someone lived near me that had the setup you talk about and I could test it out first hand.
I'm putting money away towards a purchase. It may be a while.
I would love to get a Sigma 500mm f4.5, but that's not gonna happen anytime soon... if ever according to my wife

---------- Post added 12-15-16 at 02:34 PM ----------

Pentax already covers 300 f4 to 560 f5.6 for static shots. The only thing they don't cover is 300 f2.8 or 400 f2.8 for when freezing motion is a must (fast shutter speed + medium ISO) but they would also need a kick ass AF to go with the 300/400 f2.8.
Shooting along with Canikon 400 f4 to 600 f4, for static shots they don't have much advantage over the f5.6 lenses of Pentax.

That's fair.
I know I wouldn't be able to afford a new production 400mm f2.8. That lens would likely be very large and very expensive.

---------- Post added 12-15-16 at 02:36 PM ----------

Multiple people are telling me, "If you ever want to take wildlife photography seriously, you'll have to give up Pentax"

I'm trying to find a way to prove them wrong.

Reality - If I ever want to take my wildlife photography 'seriously' - not that I don't already... - I'll likely need to sell a few organs...

[normhead]

A Pentax one would be more.... put a 1.4 on this and you are laughing.

[clackers]

Are budget-conscious Pentaxian wildlife shooters just a rare breed?

400mm f4 will not be budget-priced!

[monochrome]

There's always manual focus:
K400/5.6
K500/4.5
M*300/4 + TC
M400/5.6
A*300/2.8, A*400/2.8 & A*600/5.6
A400/4

[normhead]

I paid about $400 for an A-400ƒ5.6. From a day when people made consumer long primes, for the budget conscious wildlife photographer.
















It's not even that heavy, and focus confirmation works great, even with the 1.4 on it (but not with the 1.7.)
Slide Show...A-400 Slideshow by Norm_Head | Photobucket

[GeneV]

I'm also a fan of the A400, with or without the AL 1.4x converter. Focus confirmation on Pentax bodies works well, but the focus magnifier of the A7R is even better, though not hand held with the converter (no IBIS). This is shot full frame with A7R and A400, and cropped a bit afterwards.

[redpit]

I would prefer the classic focal length of a DFA 500/f4. This way I could also have a useful 700 and 1000mm prime with the relevant converters.

[cleaverx]

It would be nice if Ricoh would come out with 400mm f/4, but it would be too expensive. 400mm f/5.6 would be more affordable and easier to handhold.

I love my SMC A 400mm f/5.6. It produces exceptional images, easy to use so I only shoot it handheld. It is a manual focus lens, but that doesn't bothers me. Some samples with this lens.









---------- Post added 12-16-16 at 02:27 AM ----------

Multiple people are telling me, "If you ever want to take wildlife photography seriously, you'll have to give up Pentax"

Bunch of garbage. Pentax is more then capable for wildlife photography. Can it compare to flagships of Canon 1DX II or Nikon D5 with top prime lenses like 600mm f/4??,,,answer is no. But we are talking $18,000 setups.
But there is a catch.
You mostly gain with this high $$$$$ end setups auto focusing speed and accuracy and faster shutter frame rate in expense of 16 -20 MB sensors, which leaves them with less cropping flexibility. All my friends are shooting with top Canon and Nikon (mostly Canon) and at the end of the day of shooting I have just as many keepers as they do with my K-1 and K-3 using manual focus lenses. There is nothing nicer then when you nail the shot with K-1 or K-3 especially with K-1 and it's 36 MB sensor.
Another important thing is that Pentax has SR (Shake Reduction) built in body...huge advantage. You can use just about any K-mount lens and have image stabilization. In Canon or Nikon you pay big $$$$$ for a good image stabilization in their lenses.
Sony mirrorless are also great. Image stabilization in the bodies and awesome EV (electronic viewfinder).

[UserAccessDenied]

400mm f4 will not be budget-priced!

All relative.
400mm f4 is budget conscious compared to 500mm f4 or 400mm f2.8

[Kunzite]

Besides, nobody said "low budget", right? Perhaps some people are over-conscious about having lots of money on their bank accounts

[cleaverx]

I would love to get a Sigma 500mm f4.5, but that's not gonna happen anytime soon... if ever according to my wife

The 400mm f/4 would more likely cost about the same if not more than Sigma 500mm f/4.5

[Digitalis]

My opinion in TL/DR form: it wouldn't sell enough to be viable.

[cleaverx]

My opinion in TL/DR form: it wouldn't sell enough to be viable.

Yep, unfortunately Pentax share small fraction of DSLR market. But there is a good sign with Pentax coming out with electronically control aperture lens used in new PLM WR 55-300mm. That might encourage the lens makers like Sigma and maybe even Tamron starting to make more lenses for Pentax where they don't have incorporate old screw drive system , let's hope that is the case.

[GeneV]

All relative.
400mm f4 is budget conscious compared to 500mm f4 or 400mm f2.8

That is not a given. Look at the price of the Canon offering for 400/4 and the Nikon 500/4. They both seem to end up around $7,000. I would guess that once you get into specialized lenses with a small market, it is hard to get below that price point.

[UserAccessDenied]

That is not a given. Look at the price of the Canon offering for 400/4 and the Nikon 500/4. They both seem to end up around $7,000. I would guess that once you get into specialized lenses with a small market, it is hard to get below that price point.

If you're looking at the top models : The Nikon 500mm F4 is $10,296 and the Canon 400mm F2.8 is $9,999...
The Canon 400mm F4 is $6899.

Sigma even makes an 800mm F5.6 for $6500.

There are features in these lenses than raise the price point. It's not just that 400/4 and 500/4 are the same price point across the board.

you'd assume a 400/4 would be less expensive than a 400/2.8 or a 500/4 with the same exact features.