Strange Aero Ektar results (bokeh?)

I like the bokah. The lens I had, many moons ago was before the problem described as mine was clear. I would be hesitant in putting it in the sun for fear of any heat buildup that might cause separation or clouding of elements. I would use the blb only. Or if only shooting B&W leave it as is. Why put a filter in front when it effectively has one built in.

I may be strange...but I also like the bokeh. Strange and wonderful to me.

Here are some sample shots with my Aero Ektar.

The first one is in color, the second link is kind of big but highly detailed black and white version shot on Poloroid Type 55.

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The results with neutral background are much better, which makes the Aero Ektar quite interesting for portraits under controlled conditions - you just have to be more careful with the background.

Unfortunately, I was paying more attention to the distance of the subject (thin DoF) than to the facial expression

Anyway, the photo is attached...

Denis

Denis, best way to tell how 'colored' your lens is, is to place it over a piece of white paper & look thru it. Your posted image has a background roughly the color of th ediscolored glass :O) so who knows?

I'm sure you have looked at it enough times to know, but the white paper test seems to eliminate any question.

Michael, you're right, after sending the message, I realized 'of course' my 12" lens has been disassembled'. It's in a barrel, and does unscrew easily. I will only hope someone took the care to space it correctly. If they could make a 6" plus diameter tube with proper thread, I imagine they had the ability to do the rest right. (Fingers crossed).

Murray

I dont think it can be spherical abberation at all. There is one spot in the centre and this is a nice evenly illuminated disc. My own AE shows near perfect bokeh both before and behind the focal plane, even when focussed at 6', at least on axis.

The effect you're seeing is only at the corner of the frame. I suspect its actually Coma. At the focal plane, the coma blur is comet shaped, but when you defocus the Coma it becomes a distribution of light and dark like you're bokeh, also shaped by the mechanical vignetting of the lens. As far as I know, this is an unavoidable problem on fast lenses.

You may find that the blur circles look alot better if you stop down just a little. The vignetting and comma should rapidly improve. Because the AE has such a good diaphragm (15 blades?) you will still get nice creamy bokeh and you highlights should become nice evenly distributed circles. This for me is one of the attractions of the AE, I have full control of the DOF without sacrificing the image quality, and its also pretty sharp. Mine resolves around 60lp/mm at wide open and 10' distance

Keep at it (you've had a few years to play !)

Kevin.

Kevin - I assume the lens you use is a 178 mm (since it's the only one that fits a camera with ease).

Michael - My 24" is still in it's shutter body, so the secret screws must be what's stymying me. I probably don't need to take it apart - I opted to de-spring the shutter (easy access) and provide external prime mover force.

The 1939 Anastigmat probably predates the rare-earth glass design and thus shows no color center artifact.

Murray

All fast glass of the time display these round highlight artifacts wide open; and some modern lens still do !
Here is a first generation 50mm f1.4 Ashahi Pentax wide open, also with it's dose of thorium glass.


My modern cosina/voigtlande 40mm f1.4 Nokton also shows the same things, as well as the Nikon AIS and plenty others...