[pepperberry farm]

just arrived this week:




acceptable sharpness, nice colors:

[pepperberry farm]

ah, there's some old-school bokeh:



and then there's this:

[pentaxpete]

1984 Mamiya C220 and 'Blue Dot' lenses. Outdated AGFA APX 100 film home-processed in home-made ID11 1+1
Leigh -on-Sea Essex England 135mm f4.5 Sekor set

[pentaxpete]

1984 Mamiya C220 = 80mm f2.8 'Blue Dot' Sekor set outdated AGFA APX 100 in home-made ID11 Blackmore Village, Essex England

Attached Images

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[simple1]

Another hen picture with the M/S 58/1.7.

[simple1]

M/S 55/1.4 @f1.4

[pepperberry farm]

trying to get a handle on this lens...

[pepperberry farm]

[pepperberry farm]

[edom31]

K-5 IIs with Mamiya Sekor 35mm f2.8trying to get a handle on this lens.

Never seen swirls from the lens (bokeh) before... not bad - wide open?

---------- Post added 08-13-19 at 11:03 AM ----------

Few 35/2.8 shots I did not share previously:



This one in color:

[pepperberry farm]

Never seen swirls from the lens (bokeh) before... not bad - wide open?

no, more like f5.6 or so...





this is wide-open...

[Sandy Hancock]

The Mamiya 80mm on the Pentax K-1 full-frame camera has an image circle similar to a full-frame 135mm lens when installed on the K-1.

No. No, no NO!

Can we please put this to bed? If you put an appropriately adapted medium format 80mm f/1.9 lens on the K-1 it will produce images somewhere between those of the FA 77/1.8 and the FA* 85/1.4 with respect to angle of view, with about the same and slightly more depth of field respectively wide open. A full frame 135mm lens will give a considerably tighter field of view.

The size of the image circle is irrelevant - what matters is how much of that circle is recorded by a given size sensor.

If I wasn't in an airpot lounge about to fly to Seattle I'd do some test shots to demonstrate it. I have a P645 to PK adaptor, and unless I'm seriously mistaken (and please correct me if I'm wrong), my adapted DFA645 35/3.5 should give the same field of view on the K-1 as my Sigma 35/1.4 Art. Likewise with my DFA645 55/2.8 and my DA* 55/1.4, and almost with my FA645 75/2.8 and FA 77/1.8

Anyway, back to the thread; I really wish I still had my Mamiya 80/1.9 - it was a gorgeous lens.

[ivanvernon]

No. No, no NO!

Can we please put this to bed? If you put an appropriately adapted medium format 80mm f/1.9 lens on the K-1 it will produce images somewhere between those of the FA 77/1.8 and the FA* 85/1.4 with respect to angle of view, with about the same and slightly more depth of field respectively wide open. A full frame 135mm lens will give a considerably tighter field of view.

The size of the image circle is irrelevant - what matters is how much of that circle is recorded by a given size sensor.

If I wasn't in an airpot lounge about to fly to Seattle I'd do some test shots to demonstrate it. I have a P645 to PK adaptor, and unless I'm seriously mistaken (and please correct me if I'm wrong), my adapted DFA645 35/3.5 should give the same field of view on the K-1 as my Sigma 35/1.4 Art. Likewise with my DFA645 55/2.8 and my DA* 55/1.4, and almost with my FA645 75/2.8 and FA 77/1.8

Anyway, back to the thread; I really wish I still had my Mamiya 80/1.9 - it was a gorgeous lens.

Yes, I love my Mamiya 80mm f 1.9, and actually I am pleased that it demonstrably yields an approximate 80/85mm FOV on the K-1, as per the three attached shots.

Any way, here is the same subject taken from the same distance with the Mamiya 645 80mm, an Auto Sears 135mm, and the Pentax-FA* 85mm f 1.4.

It seems as you said that the portion of the M80/1.9 image circle recorded on the K-1 sensor is almost exactly the same as the portion of the PK 85 FA*/1.4 image circle recorded on that same sensor, while the Sears 135mm lens is much tighter. This is a big surprise to me as I had been thinking that using the M80 on the K-1 was yielding a tighter image than it would yield on a 645 sensor.

Later I will give the M645-35 and some Pentax 35mm a try. I will also try the DFA645 55mm f 2.8 and one of my K-mount 55mm lenses.

[ivanvernon]

No. No, no NO!

Can we please put this to bed? If you put an appropriately adapted medium format 80mm f/1.9 lens on the K-1 it will produce images somewhere between those of the FA 77/1.8 and the FA* 85/1.4 with respect to angle of view, with about the same and slightly more depth of field respectively wide open. A full frame 135mm lens will give a considerably tighter field of view.

The size of the image circle is irrelevant - what matters is how much of that circle is recorded by a given size sensor.

If I wasn't in an airpot lounge about to fly to Seattle I'd do some test shots to demonstrate it. I have a P645 to PK adaptor, and unless I'm seriously mistaken (and please correct me if I'm wrong), my adapted DFA645 35/3.5 should give the same field of view on the K-1 as my Sigma 35/1.4 Art. Likewise with my DFA645 55/2.8 and my DA* 55/1.4, and almost with my FA645 75/2.8 and FA 77/1.8

Anyway, back to the thread; I really wish I still had my Mamiya 80/1.9 - it was a gorgeous lens.

Here are two shots with K-1 and adapted Pentax-A 645mm 55mm f 2.8 and converted Canon-FD 55mm f 1.2. I did not use the D FA 645 55mm lens because it lacks an A ring, and does not play well with adapters. I selected the converted Canon lens because it is one of a very few lenses in my collection of that exact focal length.

I did not try the Pentax-FA 645 35mm f 3.5 against a K-mount because my wife has deserted me (temporarily) for the Philippines, taking my lone K-mount lens, the plastique fantastique with her, but perhaps later I will select a K-mount zoom lens and position it at the 35mm position for comparison.

[Sandy Hancock]

It seems as you said that the portion of the M80/1.9 image circle recorded on the K-1 sensor is almost exactly the same as the portion of the PK 85 FA*/1.4 image circle recorded on that same sensor, while the Sears 135mm lens is much tighter.

Same focal length on same sensor = same field of view. So, on the K-1, the Mamiya 80/1.9 will slightly wider than the FA* 85/1.4, but not by much. The size of the image circle and the format it is designed for doesn't matter.

I had been thinking that using the M80 on the K-1 was yielding a tighter image than it would yield on a 645 sensor.

You're absolutely right, but that is only because of the considerable difference in sensor area. 80mm is a normal lens on 645 format, but a short telephoto on 36x24.

Anyway, I'll bow out, because sadly I'm only an emeritus member of this club