[wilson_lwy]

Hi all,

Firstly, sorry for my poor english as I am not a native speaker. I am doing a project which requires quite some reach for the lens. I have done some tests and found out that I would need around 600-800mm lens for my Pentax 67. I am considering purchasing a 200/4 lens with 2 converters stacked or a 400/4 (old) lens with a 1.4X/2X converter. However, the 400/4 is quite a huge lens that is inconvenient for nomal use and I wonder if I will ever use it again after the project. I am kind of on the fence because I am not sure about the quality of 400/4. What do you guys think about it? Should I go for a 200mm or a 400mm lens? Thanks for all your help!

WIlson

[MossyRocks]

My understanding is that stacking converters doesn't offer much if anything that can't be done with a good crop and would mostly just make a mess of things and then there is the light loss. A good 2x matched to the lens you are using is about as good as one could get. This article came to mind when I saw your question and should provide some reasonable answers.

[UncleVanya]

My understanding is that stacking converters doesn't offer much if anything that can't be done with a good crop and would mostly just make a mess of things and then there is the light loss. A good 2x matched to the lens you are using is about as good as one could get. This article came to mind when I saw your question and should provide some reasonable answers.

That particular use was with cheap teleconverters. The moon shot (linked in the article you posted) used higher quality teleconverters:

Extra Reach for Shooting the Moon | PetaPixel

I’ve done some stacking for moon images. It’s doable with high quality glass but debatable vs cropping. If this project is on an actual 67 it’s film and scanning the negative at high resolution will be important.

[desertscape]

The 400 Takumar is quite well corrected for color and other aberrations. It does well with the Pentax 1.4X grey converter. Using two 2x converters on the 200 is not only magnifying the image but also magnifying the aberrations. The 200 with the 1.4X works fine but going much beyond that, the image starts to degrade. The 400 Takumar at f'/11 without a converter is very sharp. It is a much better lens than the 300 Takumar.

[MossyRocks]

That particular use was with cheap teleconverters. The moon shot (linked in the article you posted) used higher quality teleconverters:

Extra Reach for Shooting the Moon | PetaPixel

I’ve done some stacking for moon images. It’s doable with high quality glass but debatable vs cropping. If this project is on an actual 67 it’s film and scanning the negative at high resolution will be important.

That is true I can't stack my converters even though I was curious if the 1.4X-L could stack with the 2X-L and found out the answer is no. I think one of the biggest things is making sure one is using a quality converter that works well with your lens. In my case that is the 1.4X-L and 2X-L with the A* 400/2.8 but I would have to defer to others for the 6x7 setups.

[marcusBMG]

normhead posted in the 300mm lens club considering results from stacking tc's with the DA* 200mm f2.8. Results I thought were pretty impressive ( think the pics are now missing from the actual post), that is a sharp lens. cooltouch posted a thread on mflenses where he stacked successive tc's on his tamron 300mm f2.8. His main conclusion was that the increased magnification did pull more information from his subject: a small panel with writing on it. Previous posters have already remarked on whether cropping is a more effective way to go; along with that using eg a pentax Q or toher small sensor camera with a suitable lens gives huge 35mm equivalent focal length (~ 5x crop factor with Q) and could be a way to go. I can add that the subject is important. IME wildlife, for example, cropping tends to be the way to go, upping the focal length and therefore also F stop and therfore much slower shutter speeds magnifies all the difficulties with extreme telephoto photography: vibration, shake, subject movement. And I find that fine detail is also compromised more quickly with tc's. However subjects like ships, where a very stable setup can be used, can benefit from the inherent increased info that cooltouch demonstrated. Atmospherics, however, can often be the limiting factor in such long distance photography regardless of the mode.
In any case, if you want to try the tc route, the lenses mentioned are the type whch will work best.

[gofour3]

Check the Pentax 67 Rear Converter manual and it indicates stacking rear converters is not recommended. (See above post by Steve. (Desertscape))

Phil.

[ppohja]

I am having the 2x Vivitar 67 Pentax teleconverter, and the 300mm F4 lens. My location full moon is happening at 12th August, means one week from now.

(If remembering this, and being in my home) will shoot the moon with and without the teleconverter. My location is having some (not much, Helsinki) light noise; however I am thinking it would be beneficial for you for seeing the result.

Obvious, I am not answering to your question... I am playing with the cards I am having in my hand.

(re: @gofour3, the internet findings of your mentioned "Pentax 67 Rear Converter", is unsurprisingly telling, "Two or more cannot use").

[RICHARD L.]

Last winter, I mounted a grey 1.4X Pentax converter on my P67 500 mm f/5.6 tele, then mounted my Pentax 645Z digital with the proper Pentax adapter on it. Apart from producing a dark, difficult to focus critically viewfinder image, this combination produced surprisingly good images. Pentax does not recommend using a converter with the 500 mm f/5.6 on a P67 body, though, because of risks of vignetting. This is a heavy combination and you need a solid tripod plus Gimbal head to manage this "bazooka".

[mikeSF]

I've not used a 67 body, however I've done a full set of comparisons of cropping versus stacking TCs, with my own gear(645Z and 67/645 glass), and have been able to draw definitive conclusions from that data.

With my rig, in every case, stacking glass is always preferable to cropping away pixels. Period.

The 67 M*300/4 is a wonderful candidate for adding one or two rear converters (1.4x & 2.0x), with very impressive results.

I've also added same teleconverters to the 645 A* 600/5.6 with great results.

On my crop rig, the DA* 150-450 also excels when magnified by TC, versus discarding pixels.

Fwiw, Good luck.

[mikeSF]

I've not used a 67 body, however I've done a full set of comparisons of cropping versus stacking TCs, with my own gear(645Z and 67/645 glass), and have been able to draw definitive conclusions from that data.

With my rig, in every case, stacking glass is always preferable to cropping away pixels. Period.

The 67 M*300/4 is a wonderful candidate for adding one or two rear converters (1.4x & 2.0x), with very impressive results.

I've also added same teleconverters to the 645 A* 600/5.6 with great results.

On my crop rig, the DA* 150-450 also excels when magnified by TC, versus discarding pixels.

Fwiw, Good luck.

Here is the 67 M*300/4 with 1.4x AND a 2.0x TC, adapted to the 645Z.
Shangri-La Revealed

[Ed Hurst]

That's a stunningly marvellous shot, Mike!

[barondla]

Mystical and spectacular image mikeSF. You've totally disproved the "stacked converters are useless" urban legend.
Thanks for sharing,
barondla

[TDvN57]

Here is the 67 M*300/4 with 1.4x AND a 2.0x TC, adapted to the 645Z.
Shangri-La Revealed

Very nice shot Mike. Have you found any difference in the sequence in which the TC's are stacked?

[mikeSF]

Very nice shot Mike. Have you found any difference in the sequence in which the TC's are stacked?

I also tested that and there was a slight difference, but now I cannot recall. I will pull out my notes.
I believe i have been mounting the 1.4x to the lens and the 2x to the 1.4 most often, based on that info, but i will verify.

---------- Post added 09-13-22 at 06:50 PM ----------

Mystical and spectacular image mikeSF. You've totally disproved the "stacked converters are useless" urban legend.
Thanks for sharing,
barondla

ha, i believed it too until i started watching these wildlife shooters with multiple TCs delivering cracking bird images.

---------- Post added 09-13-22 at 06:50 PM ----------

That's a stunningly marvellous shot, Mike!

aw shuck, thanks, friend. when you come out, i can get you up there.