[littledrawe]

I would like to see samples of other converters to see what they produce. This shot is the Tamron Adaptall 2 1.4X TC and it got me thinking about how bokeh is affected by the TC. I don't like the background of the shot and I know there are things that I can do to change it in PP but I would rather not have to if I can avoid it. Does anyone have any unprocessed TC bokeh images to give us an idea of which ones may be better than others.

[Powerstroke 7.3]

I have the Rokunar 1.7 tele convertor and if you look at this post
https://www.pentaxforums.com/forums/post-your-photos/237062-nature-quick-trip-zoo.html#post2509461
, the third and forth shots have some nice bokeh. I am using it with my DAL 55-300. Also here are some more. The 1st is equivalent to 323mm, 2nd is 442mm and the 3rd is 510mm.

[Lowell Goudge]

You need to remember that the teleconverter just doubles the image, so I would expect you are seeing the same bokeh as your lens

[woodywesty]

I would like to see samples of other converters to see what they produce. This shot is the Tamron Adaptall 2 1.4X TC and it got me thinking about how bokeh is affected by the TC. I don't like the background of the shot and I know there are things that I can do to change it in PP but I would rather not have to if I can avoid it. Does anyone have any unprocessed TC bokeh images to give us an idea of which ones may be better than others.

WOW! what a fantastic shot... I'm not sure that the bokeh is all that bad but rather that it is distracting the eye away from the hawk.... might not make much difference which convertor you use? Great picture though...

[dean45]

Here is one from my film days.
lens 55mm Mamiya-Sekor f/1.4 2X screw mount teleconverter Vivitar I think.
f stop unrecorded. Distance from back seat to front seat of a canoe.
The corner & maybe edges have the teleconverter swirl even for things in focus, the ojects in the center are so out of focus
that bokeh may not apply. There are mid distance brush limbs to check for bokeh.
I had to reduce by file to less than 900 MB to upload it, my scanned file was 7.42MB, I hope there is still enough detail yo
show the teleconverter effects.

dean45

[RollsUp]

Here's few taken with my DA* 300 with an AFA 1.7 TC

[littledrawe]

You need to remember that the teleconverter just doubles the image, so I would expect you are seeing the same bokeh as your lens

Lowell, is this really true? Each lens produces a different bokeh depending on the optical elements and construction so wouldn't adding extra glass change the "look"?

WOW! what a fantastic shot... I'm not sure that the bokeh is all that bad but rather that it is distracting the eye away from the hawk.... might not make much difference which convertor you use? Great picture though...

Thank you for the compliment. I will eventually try to make the background more pleasing in PP but I just wanted an example of what I think may be happening.

Here is one from my film days.

Thanks for the shot, I love that it was taken when that life jacket was probably top of the line product.

Here's few taken with my DA* 300 with an AFA 1.7 TC

Great subjects! Since you happen to have what many consider the cream of the crop out of current telephoto lenses and a great converter, how about some shots w/out the converter and the the same shots with it for comparison??

[Lowell Goudge]

Lowell, is this really true? Each lens produces a different bokeh depending on the optical elements and construction so wouldn't adding extra glass change the "look"?

Remember though the TC function is to take a focused image and make it twice as big. It is added to an already complete lens, as opposed to being part of the complete lens

Maybe try an experiment. Take a shot with a lens, then sake a shot with the same lens, at the same focal length if it is a zoom, and from the same spot take a shit with the lens plus TC. Then crop the lens image to the same field of view and tell me what you see.

I'll bet that the images are the same.

[panoguy]

and from the same spot take a shit with the lens plus TC.

I'll tell you what I see, but it won't be pretty...

[G_Money]

Here's a crop of an image with an A*600mm + 1.4X-L converter. I think it looks a little like the donut bokeh from a mirror lens. I'm guessing it's because of the way the tc extends its optics into the body of the host lens. I'm pretty sure that if the tc was removed, the oof highlights would look different.

[borno]

It seems to me, and I use TC's frequently, they can do some strange things to the OOF highlights and foliage when they are at a particular distance from the in focus area. Even a lens with good results with no TC can get crazy. I still usually get good results, but here are a couple with a canon 300mm and a 2x.





same combo with different conditions:

[Achromatter]

I'll tell you what I see, but it won't be pretty...

That's one of the funniest typo-response combinations I've ever read on here, I nearly spit water everywhere

[Lowell Goudge]

Here's a crop of an image with an A*600mm + 1.4X-L converter. I think it looks a little like the donut bokeh from a mirror lens. I'm guessing it's because of the way the tc extends its optics into the body of the host lens. I'm pretty sure that if the tc was removed, the oof highlights would look different.

I shoot a lot with either the sigma TCs which extend just a little into lenses, or with the SMC-F 1.7x converter but I have to admit I never see artifacts like what you show

Mostly, what is see really is only perhaps slightly increased lateral CA. And not much longitudinal CA. I think however, that may be because I never seem to have hot spots or out of focus point sources in the background. What has made your bokeh so bad is really the very small but out of focus bright spots

[G_Money]

What has made your bokeh so bad is really the very small but out of focus bright spots

Yes, it's quite noticeable in the specular highlights on some shots, otherwise I think the bokeh is usually normal. But I think it's safe to say that it's a result of the tc.

[Lowell Goudge]

Yes, it's quite noticeable in the specular highlights on some shots, otherwise I think the bokeh is usually normal. But I think it's safe to say that it's a result of the tc.

What about diffraction patterns from the cusps in the aperture? Just a thought