[leonine]

Hello friends,

I wish to buy one of the two lenses mentioned from one of the friends who is more of a collector of items than a photographer who uses the items. I will be using the lens on a Pentax 645Z.

Both cannot be/ will not be used handheld. So I will be using them with Wemberley WH-200 gimbal head on a Kaiser Tiltall TC-284 tripod.

Photography subjects of interest would be wildlife in habitat and birds at rest or moving slowly. Of course I would continue to try animals in action and birds in gentle flight but without much expectation of success.

The 67 lens is 6 kg but half the price of the 645 lens which weighs approx 3 kg.

Please advise on pros and cons considering that both would be used on the gymbal head so portability is equally sacrificed, but there could be other practical issues like quality, resolution, contrast, aberration etc (and the 67 though fast is a vintage lens while the 645 is a star lens). What would you recommend in case price is not a factor?

I would be thankful for early reply if you can as the guy is eager to sell and I am eager to buy.

Regards.

[Digitalis]

As I recall from my own experience the SMCP 67 800mm f/4 lens has rather significant chromatic aberration compared the to the later M* 67 800mm f/6.7 ED. Personally I don't consider the speed of the lens to be a particular advantage as DOF is so incredibly shallow with such a long focal length @ f/4. Your choice of Tripod head is hard to fault as Arca swiss plates are mandatory when working with gimbal heads. Though I have to say I prefer heavier tripod legs with long lenses*. My rationale is that the additional mass helps keep the center of gravity low, also it makes the whole setup less prone to internal resonance and isolate it better from the influence of external vibrations. Vibration waves lose energy when they move through materials of high density also if the materials are light and relatively homogeneous in density, vibrations travel through it quicker and vibrations caused by the camera mirror/shutter action are damped less effectively.



* I prefer to use Berlebach tripods with my heavier lenses.

[Wasp]

It seems to me the the 645 A* is the one to get - a later design that also happens to be apochromatic. The extra stop on the older lens does not count for much when you will be using a tripod anyway. Lugging the extra weight around on wildlife excursions doesn't sound like much fun.

Here are some reviews to aid in your decision:

S-M-C Takumar 6x7 / Takumar 6x7 600mm F4 Reviews - 67 Telephoto Primes - Pentax Lens Reviews & Lens Database

SMC Pentax-A* 645 600mm F5.6 ED [IF] Reviews - 645 Telephoto Primes - Pentax Lens Reviews & Lens Database

[ProfessorBuzz]

Hello friends,

I wish to buy one of the two lenses mentioned from one of the friends who is more of a collector of items than a photographer who uses the items. I will be using the lens on a Pentax 645Z.

Both cannot be/ will not be used handheld. So I will be using them with Wemberley WH-200 gimbal head on a Kaiser Tiltall TC-284 tripod.

Photography subjects of interest would be wildlife in habitat and birds at rest or moving slowly. Of course I would continue to try animals in action and birds in gentle flight but without much expectation of success.

The 67 lens is 6 kg but half the price of the 645 lens which weighs approx 3 kg.

Please advise on pros and cons considering that both would be used on the gymbal head so portability is equally sacrificed, but there could be other practical issues like quality, resolution, contrast, aberration etc (and the 67 though fast is a vintage lens while the 645 is a star lens). What would you recommend in case price is not a factor?

I would be thankful for early reply if you can as the guy is eager to sell and I am eager to buy.

Regards.

The coatings on the 645 lens are going to be better; less colour fringing; lens is probably still serviceable.

[Digitalis]

It seems to me the the 645 A* is the one to get

I agree with this recommendation. the 645 A* lens is better suited for use on the 645Z.

[leonine]

Thank you friends.

I had read the reviews of both lenses. While they do explain the lenses a bit, they don't help in comparison much.

The chromatic aberration will come into play only in high contrast situations, won't it. And perhaps there are software which can tackle that during PP.

What else? What about focusing speed using the knobs on the 67 lens against rotating the barrel on the 645 lens? Which is more responsive and faster?

The extra f-stop of the 67 lens might also help in low light situations, all other things being equal.

[climbmountainway]

The 6×7 600s out there are very difficult to handle, and most are pre smc. It is a no brainer, to have no blue fringe, the 645 600 offers an APO bringing all colors resolution to the imaging plane. Spending that much, get what you are going for.

[Wasp]

The extra f-stop of the 67 lens might also help in low light situations, all other things being equal.

Without having used either lens, it seems to me that all things are not equal. The letters ED in the designation of the 645 lens means a whole lot. In short, it means that it has been designed for reg, green and blue wavelengths to focus in the same spot. The 6x7 lens design has only been optimized for two out of the three, which is not bad but not even in the same league. Apochromatic lens designs usually require one ore more aspherical elements. At the time the 6x7 lens was born, the technological ingredients required for the design and manufacture of such magic was not on the table or even in the recipe book. In practice, this means that wide open the old timer is likely to deliver rather soft images.

[Digitalis]

Apochromatic lens designs usually require one ore more aspherical elements.

Aspherics have no association with apochromatic lens design. An Apochromatic triplet design only needs glass type of altered dispersion to correct for colour errors. Aspherics are primarily used to correct for astigmatism coma and spherical aberrations.

[leonine]

Without having used either lens, it seems to me that all things are not equal. The letters ED in the designation of the 645 lens means a whole lot. In short, it means that it has been designed for reg, green and blue wavelengths to focus in the same spot. The 6x7 lens design has only been optimized for two out of the three, which is not bad but not even in the same league. Apochromatic lens designs usually require one ore more aspherical elements. At the time the 6x7 lens was born, the technological ingredients required for the design and manufacture of such magic was not on the table or even in the recipe book. In practice, this means that wide open the old timer is likely to deliver rather soft images.

Very valid points here. And the 67 lens is not even the later SMC. It is the earlier non-SMC lens.

But in real world situation, will it affect the final image quality substantially?

Another interesting thing to note is the 67 lens has 6 elements in 5 groups whereas the 645 lens has 12 elements in 11 groups for the same focal length. What does this mean in practice? Can I assume that except the fact that the 67 lens doesn't have "ED" glass elements, it would still have overall less lens aberrations due to the less number of elements?

Both lenses are in mint condition but the 645 lens is exactly double the price of the 67 lens.

[Digitalis]

the 67 lens has 6 elements in 5 groups whereas the 645 lens has 12 elements in 11 groups for the same focal length. What does this mean in practice?

The lens with the higher number of elements has superior optical quality because with that number of elements in it the aberrations are corrected to a higher degree.

Can I assume that except the fact that the 67 lens doesn't have "ED" glass elements, it would still have overall less lens aberrations due to the less number of elements?

Incorrect, The lens with fewer elements will often have significantly worse control over aberrations than a better corrected lens with a higher number of elements. With telephoto lenses chromatic aberrations are a big hurdle to overcome. In the times of Issac Newton and the development of the telescope, optical aberrations were distinctly problematic with observational astronomy. These days we have many exotic glass types to correct for these aberrations in ways that would have impressed Newton greatly. Most of these glass types typically fall under the term ED glass.

[leonine]

Thank you so much @Digitalis. This is indeed helpful.

Looks like Pentax 645 Lens is the way to go. My shoulders will be happy to carry less weight. And I could feel more privileged than Sir Newton at least as far as optics in my life are concerned

[gofour3]

As I recall from my own experience the SMCP 67 600mm f/4 lens has rather significant chromatic aberration compared the to the later M* 67 600mm f/5.6 ED.

I think you may mean the 6x7 800/4 and the M 67 800/6.7 ED?

The 6x7 Takumar 600/4 only existed in two versions, the later SMC 1971 version and the original non SMC 1969 version. There were no more Pentax 6x7 600mm lenses.

Phil.

[Ron Boggs]

Since you have friends with the lenses, it's time for you to do some borrowing...shoot them both side by side in the same light with the same colorful subjects, especially some varying shades of green. In less time than it takes to swap the lenses you'll completely reject the old non-ED lens. Surprising how reds look similar but greens look like gray through the oldy...Don't bother worrying about your tripod set up, that can come later. I'm strictly talking test shots of stable subjects. Actually, for sharpness tests you might want to have the tripod specifics worked out (you'll need an extremely heavy duty tripod to shoot this type of glass...took me a year and several tripods to get anything sharp with monster glass)...To start, set your white balance to 5000Kelvin for neutrality and minimize or shut off the various JPEG customizations. After shots at 5000K you might want to play around with some extra JPEG pop for fun. Play 'em in raw if you want, but I'm pretty certain the first couple glances at the LCD screen on the camera (JPEG) will make your decision glaringly obvious!

I did this years ago with 35mm lenses. Shot the old non-ED 500/4.5 (with minimal lens elements) and I handed my 2nd body to my neighbor with a newer star lens FA*300/4.5 (with lots of groups of elements). We shot the same feeding osprey side by side. The difference is so extreme that you won't even believe it. I guess you could "create" all the colors in post, but that's a bad work-around. Just buy the lens that works and the *600/5.6 is a fantastic lens. Have a local friend still using it adapted down to his APSC bodies and shooting grizzly bears in Alaska for a month at a time etc.

I've owned 13 different star lenses over the years and can promise you won't regret it! They are universally sharp and produce wickedly vibrant colors. The other lens will be passably sharp but with hideously awful color. I'd bet on it!

[Digitalis]

I think you may mean the 6x7 800/4 and the M 67 800/6.7 ED?

You're right, bit of a mistake there.. that is what happens when I write a post at 2AM