You are right. Or at least more right than I was. I should have been comparing the P645 400mm (effective FOV like a 320mm lens on 35mm film) to a PK 200mm lens (effective FOV with an APS-C like a 300mm lens on 35mm film.)
I haven’t weighed anything but I did look up a couple of weights. FA645-300/4.0 = 52.2oz = $3.24 per gram DA-300/4.0 = 37.7oz = $1.02 per gram stan On Dec 8, 2014, at 11:52 AM, P.J. Alling <[email protected]> wrote: > I was off a little bit, but I was comparing the FOV of the 300mm on APS-C > (1.5 crop) to the FOV of a lens on the 1.3~1.2, crop of the 645z, against the > diagonal. I also didn't do the math myself exactly, I used a tool called > fCalc. Using that tool the diagonal FOV on the 300 on an APS-C (Nikon, they > don't have Pentax as an option), is 5.42° now lest you think I'm blindly > following the tool, I did check the FOV vs 35mm format, which I expect should > require a 450mm lens and the tool agrees, more or less with a result of > ~5.5°, to get the same FOV, on the diagonal with a 44mmx33mm, (once again > they don't have the 645z but allow you to input parameters), sensor, (OK, not > exact, but as close as APS-C is to 24mmx16mm), you'd need a 580mm which would > give an FOV of ~5.4° > > The 600mm is the only real life lens I know of that came close without using > a converter of some sort. I didn't want to include a converter in the mix > because for a negligible weight penalty, (about the same as the FA 43mm), I > can add in the FA 1.7x, to get my 300mm out to 510mm, so the 1.4x on the > 600mm isn't going to get quite the same AOV and the 2x is going to be much > narrower. > > Now I didn't compare the AOV equivalent lenses of FF 35mm to the 645z because > in Pentax world FF doesn't exist, except in film, and my LX weighs in at > about 1/2 to 1/3 less than the K-5 and the various Canon and Nikon FF cameras > are closer to 645z in weight if not in size. > > Oh, you don't have to weigh your carry kit, for the 645z, I was just being > silly, and I was taking published weights off the internet, all the K mount > gear is one place, but you have to hunt for the 645 stats. > > You wouldn't carry the same mix of lens AOV equivalents as I do, those lenses > are what I've already got, that fit in my Sundog bag. If I were starting > fresh, I'd certainly get a different mix of lenses, but I'm pretty happy with > the results so change is going to happen slowly. > > Looking at what I do have to carry I really need a wider angle lens for the > short end, but analysis paralyses set in on that some time ago. > > On 12/8/2014 10:25 AM, Stanley Halpin wrote: >> P.J. - I’ll see if I can get two parallel kits together and weigh them for >> you. A reasonably precise scale will be an issue. >> >> But meanwhile, note that your calculation is off. If you were to use the >> 645Z and wanted a lens that gave you the FOV of a K-mount 300mm, you would >> be using the 645 400mm for a FOV of about 320mm. Or you would use the 645 >> 300mm with a 1.4x converter. The 300mm, 400mm, and 1.4x (and 2.0x) are all >> readily available. I don’t currently have a 645 300mm but IIRC the >> size/weight of the 645 version were very similar to the K-mount of the same >> era. (I.e., comparing A-stye to A-style.) >> >> stan >> >> On Dec 8, 2014, at 2:20 AM, P.J. Alling <[email protected]> wrote: >> >>> The camera only weighs as much as two K-3s, the lenses however... >>> >>> I'll regularly carry one body and 20-35mm, 43mm limited, 70-210mm (Vivitar >>> S1 2.8~4.0), and an A or M * 300 f4.0. Let's add up the weight there, .54 >>> lbs + .34 lbs + 1.9 lbs 1.87 lbs which gives a grand total of 6.65 lbs or a >>> bit over 3 Kilograms. The equivalent range in lenses in the 645 system, >>> would weigh... Oh hell, too much work. The equivalent angle of view for the >>> 300mm would need a mythical 580mm on the 645Z. Closest thing available >>> would be a 645 A*600 f5.6, which would weight more than my entire carry >>> kit, (4.8 Kg), (It would cost more than my carry kit, if you can find one). >>> Sadly for me the allure of the 645Z lasts until I contact my orthopedic >>> surgeon. On the other hand if I had enough studio work or people were >>> banging down my doors for my landscape photos, I'd hire a Sherpa. >>> >>> On 12/8/2014 1:20 AM, Zos Xavius wrote: >>>> Thanks for the writeup Stan. It only weights as much as 2 K-3s huh? I >>>> carry a K-5 IIs and a K-3 with grips all the time and I don't find it >>>> to be such a big deal really. I bet this would even fit in my domke >>>> f-2. You really need to stop making me want one. :) >>>> >>>> On Mon, Dec 8, 2014 at 12:57 AM, Stanley Halpin >>>> <[email protected]> wrote: >>>>> [continued from a previous “Part 1” due to excess verbosity and PDML >>>>> limits on size of posting.] >>>>> >>>>> Part 2: What is it like to use it (and is it worth the price?) >>>>> >>>>> In the above listing of some “positive” and “negative” observations on >>>>> the 645Z, I think there are more “-“ items than “+” items. But don’t >>>>> think of this as a math ... > > > -- > I don't want to achieve immortality through my work; I want to achieve > immortality through not dying. > -- Woody Allen > > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
