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Thread: Pentax 645Z Lens selection

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    Pentax 645Z Lens selection

    Which of the pentax 645 lenses, new or older versions perform well on the 645Z camera, in terms of image sharpness. I am especially interested in the wide angle lenses from pentax

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    Re: Pentax 645Z Lens selection

    The Pentax 28-45mm is ridiculously sharp, I have a few RAWs shot at 28 & 45mm at f4.5 that look sharper than many lenses do at f/8 - All the way out to the corners at that. Here are links to download them, unfortunately I don't remember where I found them:
    https://dl.dropboxusercontent.com/u/...6/IMGP0297.DNG
    https://dl.dropboxusercontent.com/u/...6/IMGP0300.DNG

    The 90mm Macro is the other new lens that I feel makes the most of the sensor.

    The 25mm prime has been discontinued, but it wasn't a very good lens for the price, so everyone's hoping they'll make a newer, better replacement... hopefully with tilt/shift.

    The 55/2.8 is a nice lens, but the corners could be better, in that they suffer from some field curvature and softness. I also have mixed feelings on it's focal length, often times it's either too long for many wide shots, or not wide enough for wide shots.

    None of the old lenses can really resolve the sensor without stopping down, and suffer from loads of LoCA wide open, expect to use CA reduction often. The 150mm 2.8 is a portrait lens, so I don't really expect to be razor sharp wide open, but it does get very good from 5.6 onwards.

    The A & FA 35mm f/3.5 primes are pretty well-reviewed, and are your best bet for getting good wide-angle performance on the Z on a budget.

    If your interest is in something like landscapes, where you'll be shooting around f/11 most of the time, most of the Pentax lenses will do a good enough job.
    Last edited by Kolor-Pikker; 14th October 2015 at 06:39.

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    Re: Pentax 645Z Lens selection

    Quote Originally Posted by Kolor-Pikker View Post
    The Pentax 28-45mm is ridiculously sharp, I have a few RAWs shot at 28 & 45mm at f4.5 that look sharper than many lenses do at f/8 - All the way out to the corners at that. Here are links to download them, unfortunately I don't remember where I found them:
    https://dl.dropboxusercontent.com/u/...6/IMGP0297.DNG
    https://dl.dropboxusercontent.com/u/...6/IMGP0300.DNG

    The 90mm Macro is the other new lens that I feel makes the most of the sensor.

    The 25mm prime has been discontinued, but it wasn't a very good lens for the price, so everyone's hoping they'll make a newer, better replacement... hopefully with tilt/shift.

    The 55/2.8 is a nice lens, but the corners could be better, they suffer from some field curvature and softness.

    None of the old lenses can really resolve the sensor without stopping down, and suffer from loads of LoCA wide open, expect to use CA reduction often. The 150mm 2.8 is a portrait lens, so I don't really expect to be razor sharp wide open, but it does get very good from 5.6 onwards.

    If your interest is in something like landscapes, where you'll be shooting around f/11 most of the time, most of the Pentax lenses will do a good enough job.
    Thanks very much for the info and links

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    Re: Pentax 645Z Lens selection

    Excellent suggestions baring one. I very much like my 25 as I often it offers a better FL than the 28 on the 28-45. 3mm does not sound like much, but for me it makes a difference. Not that K-P did not have hands-on long term experience with the 25 (since he basically a straight shooter from what I read), however many just spew out whatever they have read about this 25 lens without actually having used it.

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    Re: Pentax 645Z Lens selection

    Quote Originally Posted by algrove View Post
    Excellent suggestions baring one. I very much like my 25 as I often it offers a better FL than the 28 on the 28-45. 3mm does not sound like much, but for me it makes a difference. Not that K-P did not have hands-on long term experience with the 25 (since he basically a straight shooter from what I read), however many just spew out whatever they have read about this 25 lens without actually having used it.
    True, I haven't actually used the 25mm, but I have seen enough images and examples over the years from actual owners to get a good idea of what it's like.

    If you really need the extra 3mm, there really isn't any other option on the 645Z, but the point here is that a 5DSR or A7RII with a 17mm TS-E or the Zeiss 21mm would be an equally good option, one with perhaps fewer limitations, and certainly for a lot less money. It's not a lens I'd recommend if you're building a system from scratch specifically for taking wide shots.

    If I were to invest in a high-end system and buy an expensive lens, I'd at least want it to be sufficiently better than anything else. The Pentax 25mm suffers the same fate as the Phase 28mm, in that if you're considering a lens that wide and want it to have perfect optics, you may as well just get a tech camera instead. Except this is a bigger problem for Pentax users since they can't just pop the back off.

    I'm totally sure that there are photographers out there who took amazing shots with this lens, but it falls into the argument that you can take any shot with any lens, which while true, doesn't help justifying the price tag of either the lens or the camera body.
    Last edited by Kolor-Pikker; 14th October 2015 at 08:18.

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    Re: Pentax 645Z Lens selection

    I collate some opinions from others and observations of my own here: http://thephotofundamentalist.com/?p=2176&page=2

    The 28-45 is phenomenal, but if you are shooting landscapes stopped down, many of the old lenses are superb too (as in very impressive by any standard).

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    Re: Pentax 645Z Lens selection

    Our own "D&A" (Dave) posted a rather comprehensive review of both classic and some new Pentax 645 lenses here. His review has been so useful to me that I have bookmarked it and refer to it frequently.

    For my landscape photography, I've settled on the FA 35mm, FA 150mm, 28-45mm, 45-85mm, and 80-160mm. I also have the 55mm but rarely use it. I'm selling my 120mm macro because I use my Sony a7RII for macro work.

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    Re: Pentax 645Z Lens selection

    I just purchased a used 645z, along with a 35 A, 55 DFA and 120 FA. None of them are here yet, but I'm looking forward to comparing them to the A7rII I've been using for the past month with a Canon 24 TS-E, Zeiss 35 1.4 and Sony 90mm macro. There should be some pretty distinct strengths and weaknesses for both, but I'm curious how shooting them both will make me feel. I'm hoping the 35 A delivers, because throwing down the cash for a 28-45 would make the Pentax system considerably more pricey than it is for me right now!

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    Re: Pentax 645Z Lens selection

    My A 35 is just sharp, sharp, sharp. You should not be disappointed.

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    Re: Pentax 645Z Lens selection

    If you get a decent copy of the 35mm A, it compares very quite well with the zoom and is a superb lens. Its just that the 28-45 is even better, at 35mm. Richer colours, more contrast, less CA and a modern modern look without being harsh. The 35mm A is so very much smaller and when stopped down plenty good enough for even the most demanding user. Just be aware that the AF confirmation may be a country mile out of true focus with these older lenses, so ensure you test using live view.


    Quote Originally Posted by Mjlamott View Post
    I just purchased a used 645z, along with a 35 A, 55 DFA and 120 FA. None of them are here yet, but I'm looking forward to comparing them to the A7rII I've been using for the past month with a Canon 24 TS-E, Zeiss 35 1.4 and Sony 90mm macro. There should be some pretty distinct strengths and weaknesses for both, but I'm curious how shooting them both will make me feel. I'm hoping the 35 A delivers, because throwing down the cash for a 28-45 would make the Pentax system considerably more pricey than it is for me right now!

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    Senior Member Ed Hurst's Avatar
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    Re: Pentax 645Z Lens selection

    I second the recommendation to look at the write-up by "D&A" (Dave) who has been very thorough and insightful.

    In terms of wide angles, the 28-45 is superb. The 35mm A is extremely good (though not quite as good as the zoom). I have the 25 DA and think a) it is not quite as good as it should be in the corners but b) it is better than many people say. Not as good as the 28-45, but I would not hesitate to use it in situations where I need the extra coverage.

    In terms of other focal lengths, I love the 90 DFA, find the 55 DFA good, adore the 120mm A. The 45-85 is competent (though no better than that) up to around 65mm. I prefer the 6x7 75mm f2.8AL to the 645 75mm lens. The 6x7 105mm f2.4 provides an interesting character to shots. The 150mm is nice without being stellar. The 645 and 6x7 200mm lenses leave me a little lukewarm, though they are alright. The 6x7 300mm f4 EDIF is superb. The 645 600mm lens is very good optically but requires great discipline and hard work to use without blur.

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