Home
SearchSearch MemberlistMemberlist RegisterRegister ProfileProfile Log in to check your private messagesLog in to check your private messages Log inLog in

Bokeh with and without focal length reducer
View previous topic :: View next topic  


PostPosted: Thu Aug 10, 2017 2:50 pm    Post subject: Bokeh with and without focal length reducer Reply with quote

Hi,
I think have read somewhere that focal length reducers like Lens Turbo and SpeedBooster impact to some extent the bokeh and make it less pleasant. Have you ever noticed any difference?
I have not done extensive tests, but I do not notice any visible difference in my pictures.

Thanks.


PostPosted: Thu Aug 10, 2017 4:48 pm    Post subject: Reply with quote

That was shot using a 94mm Printer lens, with and without Speed Booster (0.72x) all wide open (f4)

without:


with:



without:


with:



without:


with:



I would assume the difference gets more prominent when using much faster lenses.


PostPosted: Thu Aug 10, 2017 5:06 pm    Post subject: Reply with quote

Here now using a f1.6/100mm VISIONAR

Without:



with:


PostPosted: Fri Aug 11, 2017 6:59 am    Post subject: Reply with quote

Crikey... that last cat photo... Shocked

Like 1 small


PostPosted: Fri Aug 11, 2017 9:16 am    Post subject: Re: Bokeh with and without focal length reducer Reply with quote

wolan wrote:
Hi,
I think have read somewhere that focal length reducers like Lens Turbo and SpeedBooster impact to some extent the bokeh and make it less pleasant. Have you ever noticed any difference?
I have not done extensive tests, but I do not notice any visible difference in my pictures.

Thanks.


From a logical point of view there shouldn't be any difference as the focal reducer acts similar to a teleconverter just the other way round; i.e. it takes the ready picture from the lens and is just decreasing the scale. However, that effect may give you the impression that the bokeh looks slightly different due to the size difference of the final picture. I did compare some pictures taken with and without the Zhongyi Lens Turbo under exactly the same conditions and I was not able to detect any real differences in bokeh.


PostPosted: Fri Aug 11, 2017 12:05 pm    Post subject: Reply with quote

One with a roof, looks like 3d image, both versions.


PostPosted: Fri Aug 11, 2017 3:39 pm    Post subject: Reply with quote

Well, the examples above don't seem to indicate any significant difference.

I was thinking that, since a focal reducer increases the FOV of a lens, hence making a wide-angle a wide-angle again with a crop-sensor camera, for instance, that perhaps what people are noticing is what one might expect to see, bokeh-wise, when shooting with a wide angle. That is, since a WA lens tends to have a greater depth of field, less bokeh will be evident due to the nature of the lens. Perhaps this is what people are seeing without realizing that this is normal WA behavior?

I gotta say, though, there certainly isn't any of this evident in the example photos above.


PostPosted: Fri Aug 11, 2017 6:09 pm    Post subject: Reply with quote

cooltouch wrote:
Well, the examples above don't seem to indicate any significant difference.

I was thinking that, since a focal reducer increases the FOV of a lens, hence making a wide-angle a wide-angle again with a crop-sensor camera, for instance, that perhaps what people are noticing is what one might expect to see, bokeh-wise, when shooting with a wide angle. That is, since a WA lens tends to have a greater depth of field, less bokeh will be evident due to the nature of the lens. Perhaps this is what people are seeing without realizing that this is normal WA behavior?

I gotta say, though, there certainly isn't any of this evident in the example photos above.


Funny, just wanted that to be noticed, 'cause I can't see differences either Twisted Evil


PostPosted: Sat Aug 12, 2017 12:48 am    Post subject: Reply with quote

As Michael indicates, we'd be more likely to see differences under marginal conditions, for example, under high-contrast lighting a bare lens might show black background, but green background with reducer. Wink.


PostPosted: Sat Aug 12, 2017 5:08 pm    Post subject: Reply with quote

Pixel peeking could reveal visible differences. Where to look?

A better way to compare is to subtract the bare lens raw image from the reducer raw image, leaving an image showing only the differences. Smile

Hmm, now I wonder how the subtraction technique for viewing image differences would work for comparing lenses!!!


PostPosted: Sat Aug 12, 2017 11:40 pm    Post subject: Reply with quote

Minolta MC 58/1.2 with Speedbooster (Zhongyi mk I, 0.72x):

(click for full resolution)



Without Speedbooster:

(click for full resolution)


PostPosted: Sat Aug 12, 2017 11:52 pm    Post subject: Reply with quote

Excellent Boris_Akunin. Thanks!


PostPosted: Sun Aug 13, 2017 1:34 am    Post subject: Reply with quote

I did some comparisons back when I had a Fuji X-E1, here's some more:

Vivitar Series 1 90/2.5 ("Bokina") with Speedbooster (eff. 65mm f/1.8) vs Minolta MC 58/1.2 without Speedbooster:
https://www.flickr.com/photos/kaktuskontrafaktus/sets/72157648665163670

Minolta MC 58/1.2 with Speedbooster (eff. 41mm f/0.85) vs Minolta MC 35/1.8 without Speedbooster:
https://www.flickr.com/photos/kaktuskontrafaktus/sets/72157648655432267

I wasn't too impressed with the fast Minoltas on the Speedbooster but the 90/2.5 worked really well:

(wide open, eff. 65/1.8, 35mm equiv. 100/2.8)


PostPosted: Sun Aug 13, 2017 7:20 pm    Post subject: Reply with quote

Well, one thing I noticed with the photos taken with your Minolta MC 58/1.2 is that there is a substantial difference in Depth of Field between the two photos -- exactly what one would expect between a "normal" and a "wide-angle" shot. Or in this case, short tele and normal. But the background bokeh remained unaffected. An interesting result.

Further, I think your Zhongyi Mk I is doing an excellent job. Makes me want to get a Mk II all the more.


PostPosted: Mon Aug 14, 2017 3:11 am    Post subject: Reply with quote

I tried biotar 75 with and without lens turbo.
Busy backgorund like trees, on edges will be noticeable different. like Michael said. different FOV
non busy background - no different


PostPosted: Mon Aug 14, 2017 6:45 am    Post subject: Reply with quote

IAZA wrote:
I tried biotar 75 with and without lens turbo.
Busy backgorund like trees, on edges will be noticeable different. like Michael said. different FOV
non busy background - no different


I think this is a different problem. Lenses like the Helioses and the Biotar show some swirly bokeh, which is more visible on full frame cameras or by using focal length reducers, just because it happens mostly at the border of the FX frame. So camera like the Fujis (APC-s), would cut the most interesting part of the field of view.


PostPosted: Fri Aug 25, 2017 7:43 am    Post subject: Reply with quote

The thing with Speedbooster is that you get FF (almost) image circle onto your cropped sensor, which means you get to go closer to achieve the angle of view of your desired shot. And because of that, your focus point got nearer and your background will be more blurred (better bokeh in someone else's sense).

In my case, I was using the Zhongyi Lens Turbo mk2 (Fujifilm X-T1 + Fujinon EBC 50mm f1.4)

normal adapter

Depth of View by Lee Wooi Chun, on Flickr

Lens Turbo

Depth of View by Lee Wooi Chun, on Flickr

I hope this is the answer you are looking for.


PostPosted: Fri Aug 25, 2017 7:49 am    Post subject: Reply with quote

Thank you very much. Your test definitely answers the question.


ahblack wrote:
The thing with Speedbooster is that you get FF (almost) image circle onto your cropped sensor, which means you get to go closer to achieve the angle of view of your desired shot. And because of that, your focus point got nearer and your background will be more blurred (better bokeh in someone else's sense).

In my case, I was using the Zhongyi Lens Turbo mk2 (Fujifilm X-T1 + Fujinon EBC 50mm f1.4)

normal adapter

Depth of View by Lee Wooi Chun, on Flickr

Lens Turbo

Depth of View by Lee Wooi Chun, on Flickr

I hope this is the answer you are looking for.