[biz-engineer]

Bokeh is difficult to compare because it very much depends on the kind of background and distance. Some lenses producing harsh bokeh can also produce soft bokeh when the background is further away. Some lenses known for a soft bokeh also produce unpleasant bokeh when the background is part of the subject (such as oblique). Aperture blades do make a difference on bokeh balls, the trend is to prefer round bokeh balls of rounded blades , but I like some of the hexagons produced by old lenses.

[reh321]

Bokeh is difficult to compare because it very much depends on the kind of background and distance. Some lenses producing harsh bokeh can also produce soft bokeh when the background is further away. Some lenses known for a soft bokeh also produce unpleasant bokeh when the background is part of the subject (such as oblique). Aperture blades do make a difference on bokeh balls, the trend is to prefer round bokeh balls of rounded blades , but I like some of the hexagons produced by old lenses.

AS I have mentioned before, my photography began as an adjunct to my interest in railroads, where the tradition is to use a fairly tight aperture to include the entire locomotive, train, or station {all of which are photographed obliquely and are fairly long} in the DoF - which is probably why I've never been interested in bokeh; to me bokeh has always been an unavoidable consequence of having to use a wider opening to get enough light on dim days.

[monochrome]

AS I have mentioned before, my photography began as an adjunct to my interest in railroads, where the tradition is to use a fairly tight aperture to include the entire locomotive, train, or station {all of which are photographed obliquely and are fairly long} in the DoF - which is probably why I've never been interested in bokeh; to me bokeh has always been an unavoidable consequence of having to use a wider opening to get enough light on dim days.

Yes, you’d need extreme DoF to capture all of a Big Boy and tender obliquely in sharp focus.

[TerryL]

I bought it pretty much to support Pentax. Maybe the will go head and start with the 85 mm, next.
Terry

[clackers]

I wouldn't say that the out of focus rendering is terrible, it is just that it could be better and to my eyes is better with the older A 50 f1.2 and newer DFA *50. .

The scenes would have been similar if you'd photographed them with the DFA*50, Rondec, have a look at:

SLRCLUB, ??? ???? ?? ????

[Mikesul]

The scenes would have been similar if you'd photographed them with the DFA*50, Rondec, have a look at:

SLRCLUB, ??? ???? ?? ????

Thanks for the link, Clackers. I am glad I decided to keep my DA* 55.

[clackers]

Thanks for the link, Clackers. I am glad I decided to keep my DA* 55.

Well, I *want* a DFA*, Mike, but making do with the DA*55 in the meantime!

[Mikesul]

Well, I *want* a DFA*, Mike, but making do with the DA*55 in the meantime!

Well, I had one for a brief time. It is, for sure, an excellent lens in every way but size. I was pleased with the images but not enough to keep it over the da* 55. Size and money were the main deciders. I am sure it bodes well for the 85 1.4.

[reh321]

Yes, you’d need extreme DoF to capture all of a Big Boy and tender obliquely in sharp focus.

Yes, this is the type of photo I'm talking about {although I probably would have stood farther from the tracks - giving a different angle}
Grand Canyon R.R., modern locomotive, Williams, AZ. - PentaxForums.com
In this case, the photographer used f/8 to get the entire train in focus - demonstrating why this discussion is so foreign to me.

[monochrome]

Yes, this is the type of photo I'm talking about {although I probably would have stood farther from the tracks - giving a different angle}
Grand Canyon R.R., modern locomotive, Williams, AZ. - PentaxForums.com
In this case, the photographer used f/8 to get the entire train in focus - demonstrating why this discussion is so foreign to me.

I saw that photo and I agree - I would have liked more of the train featured, though the composition is interesting . The point of the DA*50/1.4 is it can make the classic oblique locomotive record shot and isolate and promote a subject against a beautiful, soft background.

[biz-engineer]

I am sure it bodes well for the 85 1.4.

For the mock-up shown, I feel like the DFA85 will be too big and too expensive. Also, I'm looking for a 85mm lens that other brands and Sigma don't have, I would like to have an 85mm f1.0 under 450gr and under $500. And for me, the DFA*50 doesn't fit my needs, I much prefer 45mm focal length, 50mm is too narrow.

---------- Post added 25-03-19 at 05:07 ----------

Well, I *want* a DFA*, Mike, but making do with the DA*55 in the meantime!

Unfortunately, 55mm is an odd focal length. The equivalent of 85mm, is 56.5mm on apsc and not 55mm. I could never use the DA*55 1.4 because of not being a true 85mm equ. And on full frame 55mm is definitely not normal.

[clackers]

Unfortunately, 55mm is an odd focal length. The equivalent of 85mm, is 56.5mm on apsc and not 55mm.

(Laughs)

[Rondec]

For the mock-up shown, I feel like the DFA85 will be too big and too expensive. Also, I'm looking for a 85mm lens that other brands and Sigma don't have, I would like to have an 85mm f1.0 under 450gr and under $500. And for me, the DFA*50 doesn't fit my needs, I much prefer 45mm focal length, 50mm is too narrow.

---------- Post added 25-03-19 at 05:07 ----------


Unfortunately, 55mm is an odd focal length. The equivalent of 85mm, is 56.5mm on apsc and not 55mm. I could never use the DA*55 1.4 because of not being a true 85mm equ. And on full frame 55mm is definitely not normal.

I know what you are saying. I think the 77mm of the FA 77 is very nice on full frame, but I was never able to find a 51.3mm lens to emulate it on APS-C.

Of course, this isn't just a Pentax problem...

[Class A]

See for yourself, @Class A

Thanks for the pointer to the comparison.

However, it confirms what I thought. If the difference doesn't matter you, that's OK, but I could pick out the D-FA* 50 from the DA* 55 easily without looking at the labels. I didn't even see where the labels were at first and hence got a blind test for the first couple of comparisons. To me the difference is very obvious.

See what the DA* 55 does to the background of Rondec's cat shot or to the grass and wall in the background of the stone wall picture? It creates this false contour business that I find objectionable and others find attractive (and go all out with it with some Soligor or Zenit/Helios glass). Each to their own.

FWIW, false contours in background bokeh are the result of over-corrected spherical aberration. Either the lens designer wanted that effect or was forced to enter a compromise to achieve other design goals. But again, it's a matter of taste.

EDIT: Here's a comparison of the DA* 55's and the HD D-FA* 50 "bokeh balls" (screenshots from the comparison you provided a pointer to):
Attachment 445588Attachment 445587
The bright outer rings of the DA* 55's "bokeh balls" cause the "double lining"/"busy bokeh"/"false contours".
Notice how much smoother the HD D-FA* 50's "bokeh balls" are.

[biz-engineer]

FWIW, false contours in background bokeh are the result of over-corrected spherical aberration.

Does that mean that old lens designs that produce harsh bokeh were over corrected? Sounds strange.

Interesting info here about the design of bokeh optics.

https://www.bhphotovideo.com/explora/photography/tips-and-solutions/understanding-bokeh