[Thomas]

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I'll tell you even with all the effort that Pentax put into the 645 A* 600mm a small amount of fringing can still be seen in extreme contrast when viewed at 100%. Of course this is easily correctable. On the other hand images I have seen from the K A* 600mm fringe significantly more and the old 67 600mm fringes beyond repair.

Personally I prefer to use my 67 M* 400mm over the 645 A* 600mm. The performance is comparable even with a 1.4x converter. It does fringe slightly more but the option of having a 400mm 4.0 and 560mm 5.6 is a key advantage. In addition, it is about the same weight and length. Of course the other reason I prefer the M* 400mm is that I have a drop in polarizer for it. I have yet to ever find this item for sale individually for the 645 A* 600mm and have come to the conclusion that if I want it I will have to have somebody fabricate it specifically for me.

The ergonomics of the 645 A* 600mm are where the pentax design really shines.

Here's one:
Pentax 645 CPL Drop in Filter for SMC A 645 600mm F 5 6 Ed If | eBay

[atlnq9]

Here's one:
Pentax 645 CPL Drop in Filter for SMC A 645 600mm F 5 6 Ed If | eBay

Thomas,
You are amazing. I have been looking for one of these for a year and a half. I just bought it. I owe you big time, I had given up.

It didn't show up in my ebay notifications as being for sale since it didn't have the word "polarizer." I kept getting all kinds of notifications for irrelevant sale items because lots of items come up regularly under "Pentax 645 600" so I started making it more strict...

[Thomas]

Thomas,
You are amazing. I have been looking for one of these for a year and a half. I just bought it. I owe you big time, I had given up.

It didn't show up in my ebay notifications as being for sale since it didn't have the word "polarizer." I kept getting all kinds of notifications for irrelevant sale items because lots of items come up regularly under "Pentax 645 600" so I started making it more strict...

Glad you got it. I know how you feel, it took me about a year to get a copy of the 600mm.

[Ron Boggs]

That double extending hood on the A* 600/5.6 was also used on the F*600/4 lens from the 35mm film era. Those lenses weren't unreasonably flare prone but the super deep hood pretty much eliminated any flare risks. The "captive" hood design on those big star tele's is a very nice feature in field use--never drop or loose the hood. I sold my F*600 to a buddy many years ago and he's still shooting it now.

[atlnq9]

Ron,
Thanks. The lens hood on the 645 A* 600mm is better than the one on the 67 M* 400mm. It sure is a beauty. Now that Thomas found me a polarizer for the 645 A* 600mm I have the tough decision of which lens to use most. The A* has the advantage of that it is an A lens; the M* has the advantage of both a 400mm 4.0 and 560mm 5.6. I honestly think that the 645 A* 600mm will start seeing a higher duty. Now I just have to get the polarizer from the States into Namibia, Africa.

That double extending hood on the A* 600/5.6 was also used on the F*600/4 lens from the 35mm film era. Those lenses weren't unreasonably flare prone but the super deep hood pretty much eliminated any flare risks. The "captive" hood design on those big star tele's is a very nice feature in field use--never drop or loose the hood. I sold my F*600 to a buddy many years ago and he's still shooting it now.

[Thomas]

atlnq9, not sure if you noticed ,but a second polarizer appeared. When it rains it pours.

Pentax 645 Drop in C PL Filter for A 600mm F 5 6 Lens Mint | eBay

[seventhdr]

atlnq9, not sure if you noticed ,but a second polarizer appeared. When it rains it pours.

Pentax 645 Drop in C PL Filter for A 600mm F 5 6 Lens Mint | eBay

Yes!!! You have to be quick with things like this.

I missed out on the previous one on eBay, but I managed to get this one to add to my SMC Pentax-A* 645 600mm f5.6.

Now I'm a happy chappie!!!

Polariser arrived in New Zealand yesterday. I'll try it out in the weekend.

Regards

Chris

[Thomas]

That's great Chris and you get to use it in NZ - beautiful place.. I live in a place where a polarizer is a rare requirement. Still, I have some good opportunities for the 600mm: Old squaw riding out the wind:
NB: this is with the 1.4x; I think this lens is as sharp as any in the 645 line, as long as I stabilize it.

[atlnq9]

atlnq9, not sure if you noticed ,but a second polarizer appeared. When it rains it pours.

Pentax 645 Drop in C PL Filter for A 600mm F 5 6 Lens Mint | eBay

Yes!!! You have to be quick with things like this.

I missed out on the previous one on eBay, but I managed to get this one to add to my SMC Pentax-A* 645 600mm f5.6.

Now I'm a happy chappie!!!

Polariser arrived in New Zealand yesterday. I'll try it out in the weekend.

Regards

Chris

Funny thing these things. The market was dry of these for nearly the last 2yrs (saw two; one included with a 600mm and the other before I knew I wanted it...) then two come up very close to each other and both go to Pentax Forums members.

I don't know why Pentax didn't just include these with the lenses back then, there is obviously a demand for them now. Because who knows in your 10yr lens ownership if you will ever need it; but as soon as the lens goes out of production items like this become rare.

Edit:
Thomas, I think you will be surprised at how useful these things can be. They allow me to shoot a little later in the morning and a little earlier in the evening really helping preserve contrast on fur or textures. I rarely if ever use it to darken the sky or reduce reflections on the water, I may just be doing abstracts of sand dunes or photographing wildlife.

[Thomas]

....................................Thomas, I think you will be surprised at how useful these things can be. They allow me to shoot a little later in the morning and a little earlier in the evening really helping preserve contrast on fur or textures. I rarely if ever use it to darken the sky or reduce reflections on the water, I may just be doing abstracts of sand dunes or photographing wildlife.

Better not to make me regret passing on two opportunities at this point. I have a polarizer I can use when necessary, no easy rotation however. My typical situation is low light levels and consequently slow shutter speeds, hence my reluctance to use a polarizer. Plus, I'm saving for the 645DII!

[DandA]

Hi All,

I'm a little late to the party regarding the drop in polarizer for the Pentax 645 A* 600mm f5.6 lens. I had given up looking for one like most here about 9 months ago and then suddenly yesterday I saw one appear for sale, so I quickly grabbed it. I guess it's still pouring rain . Although I often use polarizers with certain lenses and subjects, I wasn't quite sure how often I'd find myself in circumstances where I'd find the drop in polarizer for this lens necessary or a distinct advnatage without then faing the ussual stability and loss of image sharpness with this lens. Time will tell.

The reason I haven't added a test report to my posted comprehensive list of tested Pentax 645 lenses on the 645D, is simply I wanted to get more of a feel of the lens's performance out in the field with a wide range of subjects and at various distances. What everyone here has already written about this lens has certainly been accurate.

It's been interesting to hear/read that the 67 M* 400mm lens has optical performance that can equal the 600mm f5.6 lens, especially when the 400mm is used with the 1.4x. This certainly gives food for thought, espcially that it provides two different focal lengths out in the field as mentioned.

I haven't participated recently in these forums, simply due to an enormously busy schedule but hopefully that will change somewhat. Always great postings here on Pentax!

Dave (DandA)

[desertscape]

The 5 element 1.4X converter for the 67 is amazing. I have used it on the 200, 300EDIF, 400 Takumar and 600 Takumar. No image degradation is seen.

[nomadkng]

so what we really need is a K to 645 adapter to mount K lens on this 1.4x, then a 645 to K to mount on a K5iis and we're all set?

[Thomas]

The 5 element 1.4X converter for the 67 is amazing. I have used it on the 200, 300EDIF, 400 Takumar and 600 Takumar. No image degradation is seen.

Thanks for the link. The 645 1.4x is also five elements and appears to be the same or very similar to those in the 67 version; however, the order of the elements is different: Rear Converter-A 645 1.4X Reviews - Pentax 645 Teleconverters and Adapters - Pentax Lens Reviews & Lens Database. Any thoughts on that?

[desertscape]

The one for the 645 is a similar design idea; two achromats combined with a single element. Both are afocal and have enough surfaces to correct all seven aberrations. I would bet they are similar in performance. The below design is what I suspected the 67 1.4X converter looked like before I knew the actual design.
1.4x Converter--Pentax 67 | Flickr - Photo Sharing!