[Driline]

The A400 might not be as good of a value as your Tokina, but should you decide to sell the A400 you would be able to recoup your money, or make a bit of a profit.

I find the A400 to be a wonderful, versatile lens. My favorite long tele, even though I have longer/faster/sharper.

FWIW, Photodo rates the A400 as being sharper than the Tokina 100-300/4.

Thank you for your input. If the Pentax 400mm A is sharper than the Tokina 100-300 F4 then that's one great lens and I might just have to bite. Your photo's are sharp and the rendering beautiful.

[luftfluss]

(Had to copy the bear, bird, insect, rodent format )

The skater shot is cool, and the bear spying on you is adorable

[Driline]

I think image quality will not be tremendously better, but if your Tokina lens has no A setting the Pentax lens will be more convenient to use on DSLRs

Since I'm using a converter for my Fuji X-H1 camera I have no need for the A setting. I hope the manual focus is smooth.

[luftfluss]

Since I'm using a converter for my Fuji X-H1 camera I have no need for the A setting. I hope the manual focus is smooth.

I find the manual focus to be smooth and well-damped, the throw is long for quickly adjusting focus from near-to-far, about 330°. OTOH, it's great for making minute adjustments.

IMO, the major downside to the lens is aberration control, in high-contrast areas it is there even at f/9.5.


Example...

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Last edited by luftfluss; 11-19-2021 at 05:34 PM.

[Driline]

I find the manual focus to be smooth and well-damped, the throw is long for quickly adjusting focus from near-to-far, about 330°.

IMO, the major downside to the lens is aberration control, in high-contrast areas it is there even at f/9.5.


Example...

Do you think $275 is a fair price for this lens? Or how much is too much?

[luftfluss]

Do you think $275 is a fair price for this lens? Or how much is too much?

I think $275 is an excellent price for that lens. I would go up another $100 for an excellent copy, but my thinking is of course colored by the fact that the "A" function is very useful to me as a Pentax DSLR shooter.

[Driline]

I think $275 is an excellent price for that lens. I would go up another $100 for an excellent copy, but my thinking is of course colored by the fact that the "A" function is very useful to me as a Pentax DSLR shooter.

Ok, well I'm going to keep an eye on it then and we'll see what happens. You know for the price I paid for both Tokina lenses I don't think I'll be selling them anytime soon. $40 for the 400mm and $87 dollars for the 100-300mm F4.

[Wasp]

I have a Tokina RMC 400mm and an SMC Pentax A 400mm f/5.6. The Pentax is definitely sharper and has more contrast. In good light the it actually works with the SMC Pentax 1.7x AF Converter - which the Tokina will not do. That said, the Tokina is not bad and it is a lot smaller and lighter.

[Driline]

I have a Tokina RMC 400mm and an SMC Pentax A 400mm f/5.6. The Pentax is definitely sharper and has more contrast. In good light the it actually works with the SMC Pentax 1.7x AF Converter - which the Tokina will not do. That said, the Tokina is not bad and it is a lot smaller and lighter.

I’m all for more sharper and better contrast.

[gatorguy]

I have the opportunity to purchase the Pentax A -400 5.6 for $275. Do you think it’s a worthy replacement for my Tokina RMC 400mm lens? I paid $40 for the Tokina which is in excellent condition.

For $50 more there's also an SMC PENTAX 500mm F4.5 at the site. A lot heavier and longer tho. I had the M400 for a few months and that was a physically long lens, more than I decided I was willing to carry, but if the 400 is no issue for you the 500 4.5 is worth consideration IMHO.

[Henrico]

I did a quick&dirty comparison between this three lenses:

Build quality: All great, K300 > A400 > RMC400

Shot from a tripod, object distance 55 meters, ISO800, timer set 2 sec.

Weight & Length: A400 > RMC400 > K300

Focus throw: K300 and A400 long and precise, RMC400 much shorter, reversed and internal focussing

Tripod connection: A400 yes, K300 and RMC400 no

Sharpness & contrast, see pictures. The 400's benefit the longer reach over the 300, but not by much. Pixel peeping the 300 is a real sharp lens.

Contrast is very similar. All the shots needed some "stretching of the histogram" in the same amount.

Aberrations: K300 (green/magenta), A400 (magenta/yellow) and RMC400 (green/red)

[Driline]

Henrico, I'm most interested in the optical differences between the Pentax A 400mm and the Tokina 400mm. To my eyes the Tokina looks to be a bit sharper in the images that you provided. So......I'm thinking that maybe I should just stick with what I have and forget purchasing a Pentax A 400mm at this time. What are your observations?

Thank you for taking the time to post these images.
Frank.....

Tokina RMC SL 400mm 5.6 and the Tokina AT-X SD 100-300mm F4

[luftfluss]

To me it looks like the Tokina has less fringing, too.

[Driline]

To me it looks like the Tokina has less fringing, too.

Well it looks like I stay with the Tokina for my 400mm legacy lens and forget about purchasing the Pentax A 400mm as it doesn't seem to offer any better sharpness or rendering.

[Henrico]

There is little in between them, I know that in contrasty situations the RMC frings more dirty than the A400 does. Focussing wide open is very delicate too, even in 8x live view mode. In the expanded circle you can see some more detail in the tie rap shot with the A400 compared with the RMC400. These are equivalent with 1600mm (!)

I just took the K1-JPEGS to compare. With bright light I will do another try at low ISO with my KP and RAW. The KP has higher pixel density, I will focus as accurate as possible. I will shot at F11 also, I think for these lenses this is the sweet spot.

On my monitor full screen all three lenses perform quite good. Only try not to focus a flying bold eagle, snappy AF is a must then...