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
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