A quick test of the VCL-ECU1 ultra wide angle converter

Started Jun 15, 2011 | Discussions
Antoinedub
Antoinedub New Member • Posts: 11
A quick test of the VCL-ECU1 ultra wide angle converter

Hi, after having uploaded some with/without shots taken with the VCL-ECU1 (see here : http://forums.dpreview.com/forums/readflat.asp?forum=1042&message=38645252 ), I've decided to check the impact of that converter on the sharpness.

All of these are 100% crops. The distance between the camera and the wall has been changed in order to get the same magnification.

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headofdestiny Veteran Member • Posts: 9,226
Re: A quick test of the VCL-ECU1 ultra wide angle converter

Thanks for the comparison. Do you think you could post a version of the whole pic that shows exactly where each crop is from?

ollie_b Regular Member • Posts: 163
Re: A quick test of the VCL-ECU1 ultra wide angle converter

intresting, thank for sharing !

If I understand what I see. The center and third seems good, but angle are degraded by converter.
--
http://www.flickr.com/photos/57509674@N08/

rainer_g Regular Member • Posts: 246
Re: A quick test of the VCL-ECU1 ultra wide angle converter

Thanks for sharing these. I'm quite curious because I have the converter on order, should have it at the end of the week.
To me your images show 2 things:

(1) how bad the 16mm really is at the extreme corners (now, don't understand this as a general verdict on that lens - I really like for other reasons...)

(2) The converter doesn't help IQ (actually it makes things worse in the corners), which is contrary to what most other users say here on this forum.

Antoinedub
OP Antoinedub New Member • Posts: 11
Re: A quick test of the VCL-ECU1 ultra wide angle converter

Thank you for your comments,

In order to reply to headofdestiny's message, please see the 2 shots that have been cropped (with the cropped sections visible) :

For the SELF28 alone :

For the VCL-ECU1 mounted on the SELF28 :

nb : rainer_g, I agree with your (1) and (2). I still am pretty happy I got that converter and will enjoy using it a lot this summer...

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Outrageous Junior Member • Posts: 49
Re: A quick test of the VCL-ECU1 ultra wide angle converter

I'd say both the 16mm and ultrawide don't look bad in the corner by f/8 and possibly a bit better at f/11. Still pretty good considering the size and price.

rrfischer Regular Member • Posts: 232
Re: A quick test of the VCL-ECU1 ultra wide angle converter

From the pictures you posted, I'd say that the 12mm has worse quality on all crops before f/5.6. From f/5.6 and closer, the extreme corners are worse with 12mm, but the rest is as good as the 16mm. For outdoors photography with no bokeh (which I think is the obvious use of a 12mm lens), it seems like a very good adapter.

headofdestiny Veteran Member • Posts: 9,226
Re: A quick test of the VCL-ECU1 ultra wide angle converter

Thanks for posting those. That seems to pretty much mirror what my copy looks like. It's just that very extreme corner section that sharpness falls off a cliff. A slight crop, making the 16+converter more of a 20mm equivalent lens, takes care of it for me.

willang77 Regular Member • Posts: 148
Re: A quick test of the VCL-ECU1 ultra wide angle converter

Hi,

can you let us know what aperature these shots were taken with? I assume they are at f8+.

My 16mm @ f2.8 is really bad at the corners and yours look really good.

headofdestiny Veteran Member • Posts: 9,226
Re: A quick test of the VCL-ECU1 ultra wide angle converter

willang77 wrote:

Hi,

can you let us know what aperature these shots were taken with? I assume they are at f8+.

My 16mm @ f2.8 is really bad at the corners and yours look really good.

It says in the descriptions. They go from f2.8 to f11.

willang77 Regular Member • Posts: 148
Re: A quick test of the VCL-ECU1 ultra wide angle converter

Sorry that I did not make it clear.

I meant the two photos posted 4 hours ago @ 6:55:02 PM, Thursday, June 16, 2011 (GMT)
which shows where those samples/crops posted yesterday were from.

Jonas B Forum Pro • Posts: 14,596
Re: A quick test of the VCL-ECU1 ultra wide angle converter

Antoinedub wrote:

Thank you for your comments,

In order to reply to headofdestiny's message, please see the 2 shots that have been cropped (with the cropped sections visible) :

Thanks a lot for this comparison! I have two quick questions;

  • Is there any distortion correction applied to the images?

  • Is it your impression that the performance at long distances is about the same as in these brick wall images?

nb : rainer_g, I agree with your (1) and (2). I still am pretty happy I got that converter and will enjoy using it a lot this summer...

There is nothing else but to agree. Nothing is perfect. I'm in the market for the converter and I suppose I'll crop the extreme corners in some cases. I hope I'll be able to take the extra step backwards to compensate for that in most situations.

regards,

Jonas

Mark_McD Senior Member • Posts: 1,759
Re: A quick test of the VCL-ECU1 ultra wide angle converter

Out of curiosity: what iso settings did you shoot at and were these shot in raw or jpeg?

reason I ask is that it looks more like NR being applied at the corners than falloff.

I would expect falloff on a lens this wide, especially with using an aperature like f2.8. You'll have fairly shallow DoF at that speed with any lens.

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Antoinedub
OP Antoinedub New Member • Posts: 11
Re: A quick test of the VCL-ECU1 ultra wide angle converter

Thank you all for your comments,

willang77, as you supposed, I did post the 2 pics taken at F/8. At F/2.8, corners are blurry (but on a 900 pixels wide picture, it is not that shocking...)

Jonas B, I did not apply any distortion correction (maybe the camera does when shooting jpeg... ?). I don't really have an opinion about the performance of that lens (+converter) when focusing near infinity beacause I did not use it much yet. Might be worth a test.

Mark_McD, I shot these at 200 iso and using jpeg 14M Fine (maybe in raw it would give something different... an other test worth doing).

About the test : tripod, timer set at 2s, Jpeg 14M Fine, 200 ISO, 6400K, center metering mode, DRO and HDR off, standard colors and manual focused using 14x in the center.

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Jonas B Forum Pro • Posts: 14,596
OK. Thank you. [nt]
n/t
Mark_McD Senior Member • Posts: 1,759
Re: OK. Thank you. [nt]

I would be very much interested in seeing the tests replicated @ ISO 200 in raw. This rules out NR being applied from the jpeg engine.

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willang77 Regular Member • Posts: 148
Thanks for the confirmation! (NT)

no text

technic Veteran Member • Posts: 8,932
Re: A quick test of the VCL-ECU1 ultra wide angle converter

rainer_g wrote:

(2) The converter doesn't help IQ (actually it makes things worse in the corners), which is contrary to what most other users say here on this forum.

maybe this depends on the focus distance. I have seen a few landscape (infinity) examples posted in this forum where the sharpness with converter looked as good as without (maybe except extreme corners, difficult to judge in most real life shots). Only the CA was clearly worse at the borders with the converter added, as can be expected.

headofdestiny Veteran Member • Posts: 9,226
Re: A quick test of the VCL-ECU1 ultra wide angle converter

There is certainly a chance that focus distance is playing a part. There could also be some field curvature, since the focus point was moved to each crop position.

technic Veteran Member • Posts: 8,932
Re: A quick test of the VCL-ECU1 ultra wide angle converter

headofdestiny wrote:

There is certainly a chance that focus distance is playing a part. There could also be some field curvature, since the focus point was moved to each crop position.

yes, my guess is that it is both: field curvature that changes with focus distance. I have seen the same in some other wide converters.

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