smc PENTAX-A 645 600mm F5.6 ED [IF]

yurihuta · 10-24-2009, 09:09 AM

Okay. I think I have caught the long lens bug with the 645 system. I recently got the FA 400mm f/5.6 and am thinking about the 600mm beast. Can anyone dissuade me and tell me how their copy of this giant is soft in the corners and center, renders relatively flat negatives, handles poorly or other really bad traits. If you have good things to say, please by all means share those too...

tuco · 10-24-2009, 10:55 AM

Why do you want to be dissuaded? If you need that focal length, there you go. A picture with a 600mm is better than no picture at all!

desertscape · 10-24-2009, 11:22 AM

From a design point of view the 600mm EDIF is very modern with 3 low dispersion elements and twice the lens elements of Pentax's 600 f/4 for its 67 line. Rest assured that this lens will not color fringe wide open. Its optical cross section shows the latest long lens concepts of using elements through out the entire lens barrel, not just a front group and a rear group like the older designs. The front element is actually an optical flat. This may be done to protect the next element from weathering. That next element could be fluorite since it weathers when exposed to moisture.

yurihuta · 10-24-2009, 01:30 PM

tuco: I need to be dissuaded, because this spirals out of control quickly. I am an equipment junkie. But I am really interested in people's experience with this lens. I can see myself getting one eventually, when I stumble upon a great deal.

yurihuta · 10-24-2009, 01:32 PM

desertscape: Thanks, this is really informative. It does sound like a modern design. I think the Canon fluorite long lenses also have/had an optical flat as well. My sorely missed EF 300mm f/2.8L had this in its design.

surfotog · 10-24-2009, 01:35 PM

Can't comment on the 600/5.6 EDIF, but I have the all the M* lenses ( 300, 400, 800) for the 67 and they are all great. The M*800 pre-dates the 600 you're looking at, and it is very sharp, even wide open. I would imagine the 600 is as well. All of my M* lenses are sharp wide open, and all work very well with the 1.4x converter. The long lens bug is insidious, beware, once you get the 600 you may start looking at the M*800!

yurihuta · 10-24-2009, 01:46 PM

surfotog: Thank you for sharing your experiences and impressions with those amazing M* long lenses. I think I stepped on a hive of those long lens bugs... Your lens line up is really impressive. What a wonderful range to work with.

I also picked up a 1.4x to use with the FA 400mm and perhaps the FA 150mm.

Originally Posted by surfotog

Can't comment on the 600/5.6 EDIF, but I have the all the M* lenses ( 300, 400, 800) for the 67 and they are all great. The M*800 pre-dates the 600 you're looking at, and it is very sharp, even wide open. I would imagine the 600 is as well. All of my M* lenses are sharp wide open, and all work very well with the 1.4x converter. The long lens bug is insidious, beware, once you get the 600 you may start looking at the M*800!

desertscape · 10-25-2009, 05:47 PM

What Pentax has done with their ED line is to use glass that prevents color separation VS the older designs where the colors would separate to some degree, then they would try to bring them back to focus. The glass types used to do this in the ED lenses (Barium, titanium, fluorides etc.) are quite expensive but allow the colors from each lens zone to focus at or very near the film plane. Even the uncorrected colors would focus close to the film. Older non-ED tele lenses from Pentax could not get the colors in the marginal area of the lens to focus at the film plane. They needed to be stopped down to eliminate the poorly corrected marginal rays (colors) from reaching the film. So, you could buy a 600mm F/4 for the 67 and stop it down a bit, instead of the 645 600mm. 6x7/645 adapter necessary. There may be a large price difference between the two.

*Ron Boggs* · 10-26-2009, 01:18 PM

ED! ED! ED! No time or reason to wait, get that lens, I promise you won't go wrong...either you will enjoy that focal length or you won't and can resell the lens for around what you paid. Just jump, there's water at the bottom of the cliff...I promise!
(spoken by a guy with lots of long glass for 67 and 35mm/digi--get the * lenses).

ARCASIA · 11-13-2009, 11:01 PM

Hi Yuri,

I don’t think that anyone would try to dissuade you from this lens based on optical considerations. I am sure it would be a joy to own and use. However, it is very expensive. If money is not an issue, then the decision is easy. But if not, there are options. I use the 67 400/4 Takumar with a rear converter and 67/645 adapter to get a 560/5.6. Great images at a fraction of the price…and I can use it on the 67 too. For the frequency that I use such a long lens, it suits me well.

In your case, you can even use your 400/5.6 with a 1.4 converter to get 560/8...granted, you lose a stop over the 600/5.6 and, I believe, AF confirmation, but I am sure the combination will yield good results in many bright daylight situations.

Regards, Alan

yurihuta · 11-14-2009, 09:09 AM

Thanks All. This is still something I am ruminating about. Perhaps if my contract gets extended long term it will find a home with me. So, a few more months until that time...

Alan, I do have the 1.4x converter (to bad they did not make an FA version) and have tried it on the FA 400mm f/5.6 - which gives really amazing reach for this 645 system. I don;t mind the equivalent f/8 with this combination due to some of the amazing films out there. What I do hope for is the 645D has very nice ISO 800 abilities once it is released (and then updated, so I can buy a heavily discounted used copy in a few years).

ARCASIA · 11-14-2009, 08:35 PM

That is a sensible view, Yuri. I, too, wait for heavily discounted used Pentax ED tele glass to appear, but sadly, such items are as rare as dragon's teeth. And I fear that the occurance of the 645D will only serve to increase demand, and hence prices, in the used lens market. Perhaps their rarity is testimony to how good these lenses actually are - nobody wants to sell them.

Best, Alan