The HD Pentax-DA 645 28-45mm F4.5 is a wide-angle zoom for digital Pentax medium format cameras, such as the 645Z and 645D.
This lens features the latest Pentax lens technologies, including HD and Aero Bright (nano) coating, DC in-lens autofocus, Super Protect front element coating, and in-lens Shake Reduction.
It corresponds roughly to a 22-36mm zoom on 35mm film and offers a diagonal field of view of 89-63 degrees. You may wish to consider this lens if the SMC Pentax-DA 645 25mm F4 AL [IF] SDM AW is too wide or restrictive for your needs.
The US retail price is $4999. In the UK, the lens retails for 3399 pounds.
HD Pentax-DA 645 28-45mm F4.5 ED AW SR
Image Format 645 digital
Lens Mount Pentax 645
Aperture Ring No
Diaphragm Automatic, 9 blades
Optics 17 elements, 12 groups
Mount Variant 645 AF2
Max. Aperture F4.5
Min. Aperture F32
Focusing AF (in-lens motor)
Filter Size 82 mm
Internal Focus Yes
Field of View (Diag. / Horiz.)
645 Digital: 89-63 ° / 76-52 °
Lens Cap F 82 mm
Coating Aero Bright,HD,SP
Weather Sealing Yes (AW)
Other Features AF/MF Switch,In-Lens Shake Reduction,Internal Zoom
I can recommend this lens: Yes |
| Rating: 9
Incredible edge and corner sharpness
size, some distortion
I was expecting a large lens and had read up lots in advance, but nothing prepared me for the sheer massiveness of it. It is genuinely enormous and every bit as large as a 35mm 70-200 f2.8 and much bigger than my 70-200 F4 lens. It handles fine in terms of what falls to finger, but the bulk is something to get used to. Tripod use will be interesting due to the lack of a collar, but I bought this lens for its range but also the fact that it can be used handheld, so very glad of the SR. I'm sure the tripod side will work fine.
Considering what the lens is doing (22-36mm equivalent, but on a larger sensor), image quality is nothing short of astonishing. Its tack sharp on centre from wide open and sharp right into the corners at close distances. Over long distances, it needs some stopping down, but is super-tight from f8 onwards at all focal lengths. It is so crisp that at f9.0, it is very hard to discern the edges from the centre.
Contrast is very good and viewed through the 645Z, the image is extremely bright, colourful and contrasty. I have not fully tested the SR in real terms, but it clearly works well and I can shoot at significantly lower speeds than my A7R with non-stabilised lenses.
This is a very complex lens and it changes character somewhat through the focal range and distances. I think there is curvature of the plane of focus towards the photographer at the edges, at distance, but very little up close. As I say, stopping down to f8 sort its out for landscape use and it is a no excuses lens. Simply amazing image quality that puts most prime lenses to shame. Diffraction comes into play by f11 on centre, but its very slight and f16 is still fairly respectable, so a lens I am happy to use anywhere from f8-f16 for landscapes, but with the aim of being around f8-11 if possible.
Its nice to see that it does not fall apart at one end of the range. I need to get to know it better, but from what I have seen it performs just as well at either end really (and in the middle).
CA is very well controlled, but distortion is quite noticeable at the wide end, though the profile in LR sorts that out nicely.
Massive and heavy, but it gives the sort of performance at landscape apertures I would expect from a Zeiss prime on full frame and clearly outperforms my 35mm f2.8 Sonnar for the A7R on a per pixel basis, around the edges and corners. It is closer to the 55mm FE Sonnar in sheer perfection, only it takes more stopping down to get there.
Mine was bought at a great discount with the 645Z and I cannot imagine what it would cost to have this sort of performance from Phase One or Hasselblad. Considering that even at the RRP it costs no more than a Leica 35mm f1.4, I consider it fairly good value for money.
Pentax have made the right decision making it big, because they have clearly ensured that it is optically astonishing and I have no doubt that this lens will still look very good on the next generation of sensors well in excess of 50mp. SR will have made it fatter, but for hand held work, it may be heavy, but can very clearly be used like a 35mm camera. Combined with the 645Z's ISO performance, its shooting envelope is huge.
I still can't get over the size of the thing, but I cannot stop looking at the perfect test frames it has delivered either.
This is a re-post from the Medium Format Forum, after renting the lens. The cost indicated is what B&H wanted at the time.
For me, this seems to be the ideal focal length range for landscapes on the 645Z, perhaps a little wider would be better, but this would do. Reading this forum, and people's comments on the size and heft of the lens, didn't prepare me for what I was about to experience.
It arrived Wednesday from Lens Rentals in a plain brown box. The box had a foam liner with a hole big enough for a Sigma Bigma, to fit. Inside that was the lens, with hood, inside its pouch. The lens cap looked like it came from a 1990's vintage Pentax lens, but the rest of the lens, and hood, looked new.
I put the lens on the 645Z and went out to the yard to take a few quick shots. I find the camera to be very nose heavy with this lens on it. The quick shots revealed the lens to be very sharp, and the new HD coatings do a nice job of reducing lens flare. Shots with the sun in them were very clean.
Back-lit Pomegranate Flower (28mm)
Since I'm a landscape photographer, and a big part of that is getting the equipment to the locations I want to shoot, I figured a good test would be to hike to a familiar spot. The spot I chose was a place known as "First Water", on the Mount Wilson Trail, in the Angeles National Forest here in Southern California. The hike to First Water is 1.5 miles with a a 980 foot ascent. It's not too bad if you're in reasonable physical health, but additional weight adds to the difficulty.
Mt Wilson trail Map
Once I got to First Water, I went down to the area I've shot before. I found the lens/camera combination less than enjoyable to use on slippery/unstable ground. It didn't balance well on a tripod. Perhaps the fact that the $5000 lens wasn't mine contributed to my uneasiness. Also, trying to use my Tiffen variable ND filter on this lens, with the hood, is impossible due the the close tolerances of the hood. There's little room to get your fingers in there to screw the filter on, and the hood doesn't have the little filter window some previous Pentax hoods have had. The result was I used the filter without the hood, which caused flare in the images.
First Water (28mm)
Heading back down the trail (28mm)
For me, to be able to use this lens, it would need: a) to be lighter, b) have a tripod collar so it feels better on a tripod, c) have a larger hood with provisions to use my variable ND filter. Also, I'd eliminate the optical stabilization. I don't think it's really that necessary for a focal length of this range, on a 'field camera'. That would also reduce the cost and most likely the weight and size.
A Weight Comparison:
645Z and SMCP-A 645 35mm
645Z and SMCP-FA 645 45-85mm
645Z and SMCP-DA 645 28-45mm
Wet brick (it was raining out, so a dry brick was not available)
I'm glad I rented the DA28-45 before buying one. I enjoy using the 645Z with the A35 and FA45-85, but I just could not find any pleasure in using the DA28-45, mainly because the 645Z becomes so unbalanced with that lens mounted on it. It does take nice photos though.
Some corner sharpness gives me pause. Size is a bit of an issue but because of the SR I actually use it as my goto lens. Strangely the lens is inspires me to shoot much wider more often than before. Partially I think that is because of the inherent additional DoF associated with the wider end of the lens. I tend to shoot a bit from the hip so I don't love using a tripod but I have found that the great ISO performance combined with the SR and sometimes a monopod really gives me images I am pretty happy with.
CA is a bit of an issue with this lens especially in the corners. However I find lightroom zaps it with the auto check box. All in all it isn't perfect but it is good enough that it doesn't come off the camera really at all. Expensive but worth it.
It's great to see you back on the forum! Have you considered joining the community?