[Driline]

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...

Thanks for spending time comparing these lenses. I appreciate it.

[luftfluss]

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.

Yeah, I'm thinking that even if further comparisons showed a slight advantage to the A400, the output is still going to be so close that, considering the "A" setting of the A400 is useless for you, you may as well simply enjoy the outstanding deal you got on the Tokina.

[Driline]

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...

Actually I was looking at the wrong photograph when I said the Tokina was sharper. It’s actually the middle photograph shot with the Pentax A 400 which is a bit sharper to my eyes. Still like you said not too much difference between them.

Honestly I think it depends on how much coffee I've had. Now I'm waffling again

[Henrico]

Well, now it is snowy white sunny freezing weather, these are ideal situation for an ultimate sharpness comparison between my three old budget lenses.

K300 (€90) vs A400 (€250) vs RMC400 (€80)

I am really surprised by the huge resolving power these old film era lenses show on a 24 MP APS-C sensor.

My setup:

- 100 ISO
- 2 sec timer
- steady tripod plus extra foundation of the lens front to avoid any shaking
- manual focus using live view at 16x magnification
- JPEG / extra sharpening -2
- no post processing in PS.
- I cropped all shots the same way twice, the expanded blue label has a size of 3 cm or so.
- On an object 60 meters away I can read these labels on the cables with all these lenses stopped down a bit.

















Focusing has to be done quite precise, and is a little difficult because of the shaking. These are not lenses to catch flying birds but static objects are fine targets.

The RMC maybe is the most valuable lens of this three, it is dirty cheap, extreme compact, great build and has internal focusing. At F5.6 the K300 F4 is even sharper then both 400's wide open (!)

Note: This is all about center sharpness, I did not examine borders and corners. The A400 has a wider front element then the RMC400, so there might be differences in sharpness and vignetting between those two.

---

Last edited by Henrico; 02-13-2021 at 02:54 AM.

[Driline]

Well, now it is snowy white sunny freezing weather, these are ideal situation for an ultimate sharpness comparison between my three old budget lenses.

K300 (€90) vs A400 (€250) vs RMC400 (€80)

I am really surprised by the huge resolving power these old film era lenses show on a 24 MP APS-C sensor.

My setup:

- 100 ISO
- 2 sec timer
- steady tripod plus extra foundation of the lens front to avoid any shaking
- manual focus using live view at 16x magnification
- JPEG / extra sharpening -2
- no post processing in PS.
- I cropped all shots the same way twice, the expanded blue label has a size of 3 cm or so.
- On an object 60 meters away I can read these labels on the cables with all these lenses stopped down a bit.

















Focusing has to be done quite precise, and is a little difficult because of the shaking. These are not lenses to catch flying birds but static objects are fine targets.

The RMC maybe is the most valuable lens of this three, it is dirty cheap, extreme compact, great build and has internal focusing. At F5.6 the K300 F4 is even sharper then both 400's wide open (!)

Great comparison test Henrico! Looking at my cellphone right now at work it seems to me that there is not much difference in sharpness between the Pentax A 400 and the Tokina 400. I’m finding in my own limited tests that my Tokina AT-X SD 100-300 F4 is in fact sharper at 300mm when cropped to 400mm than my Tokina SL 400mm lens.

[kayakfari]

I adapted a Canon FD SSC 400/4.5 to PK mount years ago and haven't looked back! The conversion was pretty simple, more or less just replacing the FD mount with a K flange and making a custom lever to work the aperture manually.
Turns out that on that lens the thickness of the old FD mount was just right to retain infinity (actually way beyond) when attached with a simple K flange. Only three screws hold it on however, so always hold by lens, not cam!

It's a very sharp lens, internal focus and much better IQ than the A400/5.6 from my testing. Only thing I wish for is that I had the A setting or at least open aperture metering. But focusing isn't too hard 5.6 to 8, where it's used the most.
Also the Canon lens holds up well with the Q to become a 2200mm reach. If you find one at a good price, it's a great option.

[luftfluss]

I adapted a Canon FD SSC 400/4.5 to PK mount years ago and haven't looked back! The conversion was pretty simple, more or less just replacing the FD mount with a K flange and making a custom lever to work the aperture manually.
Turns out that on that lens the thickness of the old FD mount was just right to retain infinity (actually way beyond) when attached with a simple K flange. Only three screws hold it on however, so always hold by lens, not cam!

It's a very sharp lens, internal focus and much better IQ than the A400/5.6 from my testing. Only thing I wish for is that I had the A setting or at least open aperture metering. But focusing isn't too hard 5.6 to 8, where it's used the most.
Also the Canon lens holds up well with the Q to become a 2200mm reach. If you find one at a good price, it's a great option.

Nice work! I would guess the same modification you did would also work with the FD 500/4.5...

When I want a more premium long tele than the A 400/5.6, I use the Tamron Adaptall 400/4... I really enjoy having auto-aperture.

[luftfluss]

Focusing has to be done quite precise, and is a little difficult because of the shaking. These are not lenses to catch flying birds but static objects are fine targets

.....

[Henrico]

Haha... great job!

[kayakfari]

Nice shots! And yes, with practice follow focus is possible with keepers!! The 400 is prob near the successful limit for hand held BIF.
I got the Canon really cheap, even got lucky and actually found a drop in polarizer for it! The prices have gone up now though.
The Tamron has got be be nice, but is too expensive now.

P.S. I suspect that many of the 400 and up FD lenses would be straightforward to adapt to K. I remember reading about the Ed Mika adaptations to EOS basically used a custom flange with focus recalibration. I kick myself because 10 yrs ago the 800/5.6 was going really cheap .. tsk tsk!

[Driline]

.....

Which lens is this?

[luftfluss]

Nice shots! And yes, with practice follow focus is possible with keepers!! The 400 is prob near the successful limit for hand held BIF.
I got the Canon really cheap, even got lucky and actually found a drop in polarizer for it! The prices have gone up now though.
The Tamron has got be be nice, but is too expensive now.

P.S. I suspect that many of the 400 and up FD lenses would be straightforward to adapt to K. I remember reading about the Ed Mika adaptations to EOS basically used a custom flange with focus recalibration. I kick myself because 10 yrs ago the 800/5.6 was going really cheap .. tsk tsk!

The Canon 500/4.5 L has such a good reputation, and as much as I like my Pentax K 500/4.5 I know the Canon is better... but as you said, pricey.

The Tamron 400/4 is very nice, I lucked into my copy well below market value probably because the seller's auction ended at 2 am

[luftfluss]

Which lens is this?

The A400. I feel as though my copy is sharper than what Henrico has demonstrated, but it is hard be definitive about it because I'm not shooting under the same conditions and circumstances as he is.

[Driline]

The A400. I feel as though my copy is sharper than what Henrico has demonstrated, but it is hard be definitive about it because I'm not shooting under the same conditions and circumstances as he is.

I think that lens is a dud. You should sell it to me.

[luftfluss]

I think that lens is a dud. You should sell it to me.

I think you're doing just fine with those 2 Tokinas... The A400 is practically my wife. Since I've had it, I've taken more snaps with it than any other lens.

It also works a treat with the A 1.4x-L Rear Converter...