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SMC Pentax-A* 400mm F2.8 ED [IF] Review RSS Feed

SMC Pentax-A* 400mm F2.8 ED [IF]

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5 66,089 Tue October 1, 2019
Recommended By Average Price Average User Rating
100% of reviewers $3,075.00 10.00
SMC Pentax-A* 400mm F2.8 ED [IF]

SMC Pentax-A* 400mm F2.8 ED [IF]
SMC Pentax-A* 400mm F2.8 ED [IF]

This immense lens is two stops faster than its standard A version, but it is also 5 times heavier, weighing in at 6 kg.

SMC Pentax-A* 400mm F2.8 ED[IF]
©, sharable with attribution
Image Format
Full-frame / 35mm film
Lens Mount
Pentax K
Aperture Ring
Yes (A setting)
Automatic, 8 blades
8 elements, 8 groups
Mount Variant
Check camera compatibility
Max. Aperture
Min. Aperture
Min. Focus
450 cm
Max. Magnification
Filter Size
145 mm (Rear: 49 mm)
Internal Focus
Field of View (Diag. / Horiz.)

APS-C: 4.1 ° / 3.4 °
Full frame: 6.2 ° / 5.2 °
Built-in, slide out
Dedicated trunk case
Lens Cap
Weather Sealing
Other Features
Drop-in Filter Holder,Tripod Mount
Diam x Length
165 x 325 mm
6000 g
Production Years
1986 to 2004
Engraved Name
smc PENTAX-A* 1:2.8 400mm ED[IF]
Product Code
User reviews
Two ED elements.
Manual FocusInternal FocusingBuilt-in HoodAperture RingAutomatic ApertureFull-Frame SupportDiscontinued
Price History:

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Site Supporter

Registered: November, 2017
Location: Minnesota
Posts: 2,726

5 users found this helpful
Lens Review Date: October 1, 2019 I can recommend this lens: Yes | Price: $2,700.00 | Rating: 10 

Pros: Super sharp, really fast
Cons: heavy, possibly some coma wide open
Sharpness: 10    Aberrations: 10    Bokeh: 10    Handling: 9    Value: 10    Camera Used: K-3   

So I recently got this monster of a lens after looking for a non messed with copy for about a year (there was one on ebay for a while that had been converted to EF mount or some such thing). Like everyone just about everyone who starts out in photography I initially wanted a huge lens but at the time didn't know what I would do with it and eventually realized that big lense like this are really a specialty thing. Go forward 20 years and I found that I do have a need for a monster like this when going astrophotography. Given the rarity of this lens and that most who own it use it for wildlife there weren't' many images to show how it does for astrophotography. Well it after finally getting a chance to shoot some astro with it I can say it is an excellent lens for that purpose as well. Yes it is heavy but then we all knew that as it has that huge slab of glass in front but it makes my 300mm f/4 look like a toy when they are next to eachother. At 400mm I have been able to use astrotracer to get fairly consistent good 20 exposures, nice point stars. You will need a big tripod and head to support this monster. The tripod I use is one I made out of 2x4s and it weights in the 60lbs range but would safely support probably 500lbs. The head I'm using on it is a manfrotto 3047. This setup is rock solid even in windy conditions.

My only issue is that it may have some coma wide open. I say may because I'm not sure if the origin of the coma in my Andromeda shot is from the lens or is from the Hoya red intensifier that is in the drop in filter holder. The next time the weather cooperates I will probably do a test where I pull that filter and try a good UV filter, and also try a shot with no filter in the holder. The lens focuses far enough past infinity that achieving the correct focus without a filter shouldn't be a problem.

The only 2 thing's I've shot with it so far have been the moon and Andromeda. Below are some pictures but for the moon shot I didn't have a bahtinov mask for focusing for it yet so while it was really close to the correct focus I can guarantee that it wasn't perfect like it was for the Andromeda shot.

The Moon at f/4:

The Andromeda galaxy 193x20s images at f/2.8 stacked and processed:

I finally got a chance to use this some more and instead of playing spent some time learning it. This time out there was substantially less coma wide open even with the hoya red intensifier in it. I did some shots with the red intensifier, top end promaster UV filter, and no filter in it to see how it would perform. After each change the focus was corrected to be correct again using a bahtinov mask. All shots at f/2.8 has some very slight coma and stars were a bit bloated however there didn't appear to be any difference between the uncoated hoya red intensifier and the top end multicoated promaster UV filter (the one in the red case) but the bloat of the stars was noticeably larger with the no filter shot. So the takeaway here is that you really need some sort of filter in this lens.

As far as coma the only thing I can think of is that I didn't give the lens the first couple of times out enough time to come into thermal equilibrium. The first couple of times I only let the lens acclimate for about 30 minutes. This time I let it sit out for 2 hours so it really had a chance to fully come into thermal equilibrium. This is probably what is really needed given the mass of this lens if one is going to do shooting like this.

I also did some testing to see where this lens looks to first reach it's peak and that appears to be around f/3.5. This was done by seeing at which point the brightest star in Cassiopeia was at its minimum size. I did 1/3 stop steps from f/2.8 to f/8 increasing ISO by 1/3 stop each time to maintain the same brightness with a 10 second astro tracer exposure. The star was centered each time and focus was checked before each shot as well.
Loyal Site Supporter

Registered: August, 2007
Location: Apiary, Oregon
Posts: 1,181

2 users found this helpful
Lens Review Date: October 21, 2011 I can recommend this lens: Yes | Price: $2,800.00 | Rating: 10 

Pros: Optical quality beyond expecations
Cons: weight
Sharpness: 10    Aberrations: 10    Bokeh: 10    Handling: 7    Value: 10   

I believe one can truely describe this lens as a rare monster. I acquired mine from KEH as a bargain buy. Nothing wrong with it but the paint showed a lot of use. If you ever have the opportunity to use one, you will be honored. The first thing you will notice is the extraordinary weight (around 13 lbs.) Though well balanced, it is just plain heavy.

This lens is out weighed in all of pentax history only by some even longer glass.
The Pentax 600 f/4, the Pentax 1200 f/8, and the Pentax 2000 reflex all weigh more but not by a lot. For filters you can use a 145mm front screwin filter, or a small dropin filter in the back.

The optical quality is dazzling by any standard, though accurate focusing is difficult at least without an aftermarket focusing screen designed for manual focus if you are using a digital body.

Use of a tripod or other support (like a concrete wall and a bean bag) is obligatory. Careful selection of a tripod is also needed. Most of the less expensive ones
are neither suitable nor rated for the weight of this lens. The heaviest and most expensive choice in your favorite manufacturers lineup should be about right. If you see the model in a Television studio holding up a camera for the 6 O'clock news, it's about right.

The lens looks and works like its baby brother the A* 300 f/2.8 except that it weighs twice as much (6kg as compared to 3kg) and takes a 145mm front screw in filter which is not routinely stocked by Walmart.

This lens remained in production (by speical order only) until 2004 when pentax dropped
allof their exotic lenses from its line up. It was never upgraded to a F* or FA* version (unlike the 300 f/2.8 and the 600 f/4) leading me to suspect that it is/was less popular than those focal lengths and is probably not a model that you will see in production again.

In a lot of ways, a lens like this really cries out for the use of a converter, but the true usefulness of a converter diminishes with every generation of digital camera, as the converter merely optically crops the image before it gets to the sensor, and if the sensor is good enough, a behind the sensor, digital crop in Photoshop will produce the same results.

In the film days you could take a lens like this, and add a couple of different converters
to your bag of tricks, and have a "poor man's zoom" Maybe better than a zoom because it was faster, but you could get a choice of effective focal lengths, but with the new reality that result in the digital crop providing results comparable to the optical crop (diminishing the value of a converter), the idea of buying a 400 f/2.8 and a 1.4X converter for use as a 'more flexible' alternative to a 600 f/4 is simply not true.

On the otherhand if if a 600 f/5.6 is the best you can get your hands on, this lens plus
a converter remains a very viable option. It has more depth of field than the 600, and a converter doesn't change this. The relatively slow speed of the 600 F/5.6 makes it very unfriendly to the Adapter 1.7x and marginal to any converter if the lighting is difficult so no one is going to pry this lens out of my hands even though I own an A*600 f/5.6.

If fast and long are what you are looking for----and you can find one of these rare birds you have arrived. It compares favorably to anything that Pentax has ever produced except for the FA*600 f/4. which is nearly impossible to find and likely far less affordable if you can find one.

this photo taken 1/100 sec at f4 and modestly cropped.
Site Supporter

Registered: March, 2009
Location: Virginia Beach
Posts: 2,950

3 users found this helpful
Lens Review Date: October 24, 2010 I can recommend this lens: Yes | Price: $3,400.00 | Rating: 10 

Pros: Fast enough to work great with TCs, high IQ, quality build
Cons: ITS HEAVY, too difficult to use a CPL
Sharpness: 10    Aberrations: 10    Bokeh: 10    Handling: 9    Value: 9   

No doubt the most solidly built lens I have ever touched. Has the feel of a high-end scientific instrument. Manual focusing is enjoyable, especially with a split-prism focus screen. The position of the mount lets the lens balance very well once a camera is attached, with or without grip and a flash. I have never had to process shots for CA even though I shoot white egrets almost daily. On dreary days I can still shoot at reasonably high shutter speeds due to the f2.8 aperture. Shots at 2.8 lack the tack sharpness of f4 and above though but its still very usable. I can add the Pentax 1.7x AF TC and get great sharpness and good shutter speeds with the 680mm/f4.5 combination, usually stopped down 1 full stop. I rarely miss AF but there are times when very close moving targets beg for AF with less than an inch DOF to work with. All in all, its a great lens to have inside pointed out a sliding glass door overlooking a wildlife habitat or feeders. The addition of TCs give 400, 560, 680AF and 800mm focal lengths although the 2xL does cut into the IQ where as the 1.4xL and 1.7x AF its usually not noticable. Stacking the 1.4xL and 1.7x AF cut the IQ to about that of an inexpensive 300mm zoom. But if you need 952mm/f6.8 it gets you there.

Drawbacks? Since the required rear filter is screwed into a drop-in holder, CPL is very difficult to use. Plan on just leaving a quality, clear filter in there (some kind of filter is required for the optics to focus properly). Lastly, go to the gym and beef up before trying to carry this 13lb lens plus 10lbs of tripod and gimbal. Although Canon has just released a 400/2.8L AF lens that is 3.8kg instead of the Pentax 400 at 6kg, if it means creaky plastic instead of smooth turning metal rings I will just keep working out. I will say that once you get it on site you will be nothing but happy its there.

I rate it a 10 even though AF, less weight and a usable filter system would only improve it. I did not discount those items since it was designed to be MF there is not a shortcoming and given the choice of ONLY AF or ONLY MF its a no-brainer with this lens to go MF. The weight is due to the build quality and huge lenses. The filter system is too minor to discount a point, even though I love CPLs! For those that followed the sale of this puppy, yes, I actually paid $3,900 total but that included both 1.4xL and 2xL rear converters I am calling $500 worth.

Recent shot with A*400 + 1.4xL (Sunrise with the Eagles)
Site Supporter

Registered: July, 2008
Location: Baltimore, Maryland
Posts: 11,587

4 users found this helpful
Lens Review Date: February 16, 2010 I can recommend this lens: Yes | Price: $3,400.00 | Rating: 10 

Pros: Amazing IQ! Fast & Long. Performance with Pentax TC's
Cons: Big, Heavy & Expensive

I second everything Tom said above. The IQ is superb (and I'm talking about the complete package--resolution, clarity, color, contrast & bokeh.)

I've only had mine for about three months now and I'm starting to get the hang of it. It matches up virtually seamlessly with the Pentax FA 1.7x AF and 2X-L TC's. What surprised me this weekend was that it's giving me shots with that "Pentax pop" that I associate with the FA Limiteds.

So it's big, heavy and expensive--$500 400mm f/2.8 pancake lenses are hard to find.
Forum Member

Registered: September, 2008
Location: NW Louisiana
Posts: 67

2 users found this helpful
Lens Review Date: January 25, 2009 I can recommend this lens: Yes | Price: N/A | Rating: 10 

Pros: Great image quality. It's a vacuum cleaner for light!
Cons: HEAVY. Manual focus

Stunning lens. As with any 400mm f/2.8, it's huge. Think "salad plate" for the size of the front element. It's 13 pounds. It's worth it -- if you need it. Works great with the matched multipliers from Pentax.

Very few of them around.

I once used this one to shoot a two-page, full-color spread in a national magazine which was a setup shot done at about 25 feet. It was a closeup for a product story, but this lens worked perfectly for that.

I'm selling my 400 f/2.8 because I am getting out of Pentax for another system. Hate to lose this lens. It's astounding.
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