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01-24-2012, 10:30 PM - 1 Like   #1
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Pentax A* 400/2.8 ED[IF]

This is one of the less common variants of the famous Pentax family of exotic lenses.

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It's one of those pieces of glass that you are a lot more likely to read about than ever actually own, but it is useful to understand what a piece of glass like this is capable of. The bird shot is of a Steller's Jay. While it's probably a long way's from the most exciting photo of a Steller's Jay ever published my point in publishing it is to make a point that a lens like this makes things possible that simply couldn't be done with less
exotic equipment. The photo is about 25% of the original frame. The Camera used for the jay photo was a K-5, not the K10D shown with the lens. The thing that speaks well of the combination is the difficult lighting. The snow in the background through the lightmeter into a tizzy so the exposure was increased by 1.5 stops in the camera, (and a little more in Photoshop) during development as it was taken raw.

I had already tried to get some usable photos with an F/5.6 telephoto and failed, which is why I brough out 'the beast'. This photo was taken at ISO 1600 (thanks to the K5 that works that high), and at 1/200 at f5.0. All in all its really pretty bad lighting to require those numbers. The lens weighs in at 6 kilos (around 13 pounds), leaving no question nor doubt but what a sturdy tripod is going to be used. For focusing, I used live view and set the focus ahead of time on the splinters sticking up in the stump. This 400 has an amazing 145mm front end on it should you want a front filter, but will take a 49mm rear filter. It also works with all of the Pentax classic converters.

In the larger picture, I'm not a great fan of the 400mm focal length. As I have often written it's too short to be a really long lens and too long to be used for larger animals. What it does do is make an amazing foundation for reaching out with a converter. The 1.4x-L converter will cost you
1 f stop of speed and a focal length of an effective 560 (40% of 400), and the AF 1.7x adapter will make thte lens auto focus (although not to its full manual range) and stretch the focal length 70% to 680m. While these devices extract a price in optical quality, the lens has some to spare,
and the more optical cropping you do with a converter, the less digital cropping you can do in Photoshop.

In the particular case here since I was relying on the bird coming to me instead of me going to the bird, I resisted using a converter and clipped
the image later, since I couldn't be sure exactly where the bird would be, but I was also dealing with a medium sized bird at 10 meters. The field of view of a 400mm lens is roughly 10% of the distance (the Cosine of 6 degrees is 0.96 for those rusty on geometry).

If you look at list prices of the 400/2.8 and the 600/4.0 (of other manufacturers who presently make them) you will see that the two are similarly
priced, but for similar money unless the birds you want to photograph all hang out within 10 meters of you (or less), the 600mm mostly makes more sense for similar money. When the best 600 around was the Pentax A* 600/5.6 there was a place for the 400/2.8 because as I have noted it would outperform the 600/5.6 in difficult lighting situations.

It is no accident that Pentax never bothered with an FA* 400/2.8, It simply cannot outperform a 600/4.0. Both are too heavy and too expensive to be volume sellers, and with only a 1 stop advantage to start, converters will more than burn that away to reach 600mm range with at least some image quality penalty. Don't get me wrong, this lens obviously is capable of magnificant photos, and is a viable alternative to longer lenses that are f5.6 or slower, which is why this article is about my A*400/2.8 instead of my A*600/5.6


Last edited by rvannatta; 04-21-2012 at 09:24 PM.
02-19-2012, 03:25 PM   #2
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Another shot of a Stellar's jay with better lighting with the Pentax-A 400/f2.8

Last edited by rvannatta; 02-19-2012 at 03:45 PM.
02-19-2012, 08:31 PM   #3
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I've owned this lens and totally agree with this:

QuoteOriginally posted by rvannatta Quote
What it does do is make an amazing foundation for reaching out with a converter. The 1.4x-L converter will cost you
1 f stop of speed and a focal length of an effective 560 (40% of 400), and the AF 1.7x adapter will make thte lens auto focus (although not to its full manual range) and stretch the focal length 70% to 680m. While these devices extract a price in optical quality, the lens has some to spare,
The optics are superb; however, it is, without question, a tripod lens. Its weight & shape make it a poor match with a monopod (and hand-holding, out of the question.)
02-25-2012, 07:12 PM   #4
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QuoteOriginally posted by dadipentak Quote
I've owned this lens and totally agree with this:



The optics are superb; however, it is, without question, a tripod lens. Its weight & shape make it a poor match with a monopod (and hand-holding, out of the question.)
Indeed, I broke down and ordered a Gimbel mount the other day because of this lens. I've bought a sturdy tripod and a good head of a classic type (bogen/Manfrotto), but at the end of the day, if you don't clamp it hard enough it doesn't stay where you put it.

but clearly is it not one of those 'walking around' lenses.

02-25-2012, 07:31 PM   #5
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I have not used this lens but the super tele lens I have used all suffer from vibration to some degree and It may be helpful to have the assistance of the Manfrotto 359 support. It is as close to using two tripods without using two tripods.
02-26-2012, 10:30 PM   #6
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QuoteOriginally posted by littledrawe Quote
I have not used this lens but the super tele lens I have used all suffer from vibration to some degree and It may be helpful to have the assistance of the Manfrotto 359 support. It is as close to using two tripods without using two tripods.
I"ll certainly consider your suggestion. I have seen some evidence of vibration on distant shots. That lead me to buy one of manrfortto's 3046
tripods-----which is a 6 legged monster often seen with TV cameras on top of it.



The balance of the 400 is less than perfect and of course the balance of the A*600/f5.6 which I also use is about 5 pounds off. It needs about a 6 inch offset plate. I use a remote release which helps, or a timed delay release if feasible, or the mirror lockup and release solutions to minimize
the issues. I've actually contemplated buying a K-01 for use on this long glass, because of its lack of moving parts. You don't have to worry about
mirror slap reverberating through the machinery if there is no mirror. Lots of people have flipped their wig at the K-01, but I see an opportunity
that I want to explore in it. One of the things about this long and expensive glass is that there is a learning curve with it, and what you think you know may well not apply, or produce different results. I figured this out real fast when I waltzed out with my optical converters and compared the results to digital cropping. I had expected the converters to provide equal or slightly better results than digital cropping, but I had to clean up my technique considerably before I could do that. I was very confused the first time I ran a comparison and had better results with the digital crop than the optical crop. Common sense told me that couldn't be. You might get the same, but the image has to go through the optics
to get to the sensor..... This led me to look at bad technique very carefully.

I'm really a great proponent of 'bean bags'. A beanbag on a block of concrete is hard to beat for stability--It's just more difficult to move.
02-26-2012, 10:53 PM   #7
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QuoteOriginally posted by rvannatta Quote
A beanbag on a block of concrete is hard to beat for stability--It's just more difficult to move.
Time to get that one into the R&D phase
02-27-2012, 10:12 AM   #8
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QuoteOriginally posted by littledrawe Quote
Time to get that one into the R&D phase
When you are a logger, finding something to move the concrete block isn't a problem. the real problem is moving the thingy that
moves the concrete block:



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