Proxel Lens Corrector

Started Aug 28, 2006 | Discussions
John Bean (UK) Forum Pro • Posts: 18,035
Proxel Lens Corrector

I was intrigued a few weeks back when I saw mention of a new "Lens Corrector" called Proxel. So what makes it different from (say) PTLens enough to make me take an interest? Read on.

The software wasn't complete at the time but I could see a major advantage for me over the competition; I had just bought my Sigma 17-70 and one of it's weak points is barrel distortion below about 24mm - and PTLens had no profiles for this lens on a 1.5 crop factor. I wanted a simple method of profiling a lens myself but it was too much like hard work... until now.

With a bit of arm-twisting I got myself enrolled as a beta-tester and spent much time playing with - and trying to break - the Proxel lens corrector. I didn't break it (well, not a lot!) but I did suggest a few tweaks here and there - and now it's a real product - see http://www.proxel.se/

It works very well, the calibration is almost entirely automatic - I just used a door frame as a target. Once saved to a file the profile can be used by a Photoshop automation plugin which has some unique features the main one being how it handles cropping and resizing. Look at this Zenitar image:

If you correct this with PTLens you get this, which then needs final cropping:

Note that the overall size is unchanged so the important centre area is much reduced in size - a permanent loss of resolution. The Proxel corrector enlarges the canvas as needed so as to retain the full centre resolution, which makes a huge difference. It also automatically crops:

Please note that these three images are to exactly the same scale.

Back to the Sigma: I had a profile done in minutes and it works very nicely. This shot in York is probably "ok" uncorrected because some of the distortion is disguised by the irregular building:

But this is much better:

I'd like to see other features added like CA correction for example, but the lens distortion correction is hard to fault and the profiles are unbelievably simple to create. It's definitely worth a look.

Usual disclaimer - I have no connection with Proxel other than doing some unpaid testing that was mainly for my own benefit, and I liked what I tested

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jhpatmore Regular Member • Posts: 371
Re: Proxel Lens Corrector

Absolutely facinating.

I presume you would have to do all other pp first and do this correction last. Might that mean several 'goes' at it?

The fudge shop in the Shambles?
James

OP John Bean (UK) Forum Pro • Posts: 18,035
Re: Proxel Lens Corrector

jhpatmore wrote:

I presume you would have to do all other pp first and do this
correction last. Might that mean several 'goes' at it?

Quite the reverse - I do it as the very first step so the profile matches perfectly. These had no PP at all so as not to skew the result but I'd normally do final corrections in Photoshop after the "automatic" one - stuff like minor rotation and/or perspective correction.

The fudge shop in the Shambles?

Yes indeed

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baldeagle21b Contributing Member • Posts: 973
Re: Proxel Lens Corrector

If you download and install the demo, reboot before running it. Otherwise the executable can't find the path to the graphics libraries and gives you an error message. Maybe this was in the installation instructions but I don't remember reading it.

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barondla Senior Member • Posts: 1,604
Re: Proxel Lens Corrector

I would like to use this with the Pentax DA 10-17 fisheye zoom. It says you have to tell it the focal length. Would you just do a few of the possible focal lengths on the zoom? Says it doesn't like raw. So is it okay to shoot in raw and convert to tiff or do you have to always shoot in jpeg (yuck). Are all Pentax 6MP bodies the same or would you have to recalibrate moving from DS to K100D? I am sure the K10D would be different than the 6MP bodies? On the website it had a square with 34 for the price. How much is it to buy? This really looks like the best way to fix lens problems. I have the fisheye zoom now I need a defish program.
thanks
--
barondla

OP John Bean (UK) Forum Pro • Posts: 18,035
Re: Proxel Lens Corrector

barondla wrote:

I would like to use this with the Pentax DA 10-17 fisheye zoom. It
says you have to tell it the focal length. Would you just do a few
of the possible focal lengths on the zoom? Says it doesn't like
raw. So is it okay to shoot in raw and convert to tiff or do you
have to always shoot in jpeg (yuck). Are all Pentax 6MP bodies the
same or would you have to recalibrate moving from DS to K100D? I am
sure the K10D would be different than the 6MP bodies? On the
website it had a square with 34 for the price. How much is it to
buy? This really looks like the best way to fix lens problems. I
have the fisheye zoom now I need a defish program.
thanks

Lots of questions! Most can be answered by actually trying it - it's easier to do than to explain!

Just to clear up one point - it's a Photoshop plugin so it works on the image currently open in Photoshop, whether that came from a raw file, a jpeg, a tiff... it doesn't matter. Once it's open in Photoshop it's just an image.

With zoom lenses you need only take a few measurements, the plugin will interpolate the rest. DS and K100D will use the same calibration.

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Jonas B Forum Pro • Posts: 14,596
Re: Proxel Lens Corrector

Thank you for the report. To me it is great being able to make profiles for whatever lens. And when it takes a couple of seconds only it is better than great, whatever that can be called. Super! or is that German?

-- hide signature --

Jonas

John Lai Senior Member • Posts: 2,579
Re: Proxel Lens Corrector

John Bean (UK) wrote:

I'd like to see other features added like CA correction for
example, but the lens distortion correction is hard to fault and
the profiles are unbelievably simple to create. It's definitely
worth a look.

Like colour, lens softness, vignetting, dynamic range optimisation corrections, but I doubt it is possible as this will need sophisticated measuring instruments.

John

OP John Bean (UK) Forum Pro • Posts: 18,035
Re: Proxel Lens Corrector

Jonas B wrote:

Thank you for the report. To me it is great being able to make
profiles for whatever lens. And when it takes a couple of seconds
only it is better than great, whatever that can be called. Super!
or is that German?

Works for me, German or not...

I did say "minutes" rather than "seconds" though

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Jonas B Forum Pro • Posts: 14,596
Re: Proxel Lens Corrector

John Bean (UK) wrote:

I did say "minutes" rather than "seconds" though

Not important. Count them and soon enough they turn to minutes. What I did pay extra attention to was this: "and the profiles are unbelievably simple to create".

Thomas Niemann Veteran Member • Posts: 4,354
PTLens update

Just finished doing a profile for a 1.5 multiplier for the Sigma 17-70 for PTLens.

I do have a question. It was my understanding that Photoshop plug-ins can't change the aspect ratio of an image. However, per your examples, this is possible. Am I interpreting you correctly?

OP John Bean (UK) Forum Pro • Posts: 18,035
Re: Proxel Lens Corrector

Jonas B wrote:

John Bean (UK) wrote:

I did say "minutes" rather than "seconds" though

Not important. Count them and soon enough they turn to minutes.
What I did pay extra attention to was this: "and the profiles are
unbelievably simple to create".

They are indeed. It takes longer to take the pictures and copy them to the PC than to actually make the profile.

I started off by being too clever by trying to pick a "perfect" target, but simplest is best and as long as the image has long, straight lines near the edge (like a door frame) it works perfectly. It doesn't mind a bit of blur either - in fact it applies some before it finds the edges - so hand-holding is as good a way as any. I found that the less I tried to be clever the better it worked.

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OP John Bean (UK) Forum Pro • Posts: 18,035
Re: PTLens update

Thomas Niemann wrote:

Just finished doing a profile for a 1.5 multiplier for the Sigma
17-70 for PTLens.

That's good to know Thomas, I've always used PTLens in the past and very good it is too, in some ways better than Proxel in terms of the available tools for CA correction, etc. But the big attraction for me was your next question:

I do have a question. It was my understanding that Photoshop
plug-ins can't change the aspect ratio of an image. However, per
your examples, this is possible. Am I interpreting you correctly?

Yes you are. It does change the canvas size to match the corrected image rather than shrinking it to stay inside the original bounds.

It's an automation plugin rather than a filter, I understand that this is what allows the canvas size change. It gives me a huge advantage in central resolution of corrected fisheye images compared with any other correction tool I've tried.

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Roland Karlsson Forum Pro • Posts: 27,539
Re: Proxel Lens Corrector

baldeagle21b wrote:

If you download and install the demo, reboot before running it.
Otherwise the executable can't find the path to the graphics
libraries and gives you an error message. Maybe this was in the
installation instructions but I don't remember reading it.

It was a miss by us - it is fixed in 1.0.1.

We hope! It seems actually to be harder to get a correct Windows installer than to do a correction tool

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Roland Karlsson Forum Pro • Posts: 27,539
Re: Proxel Lens Corrector

barondla wrote:

I would like to use this with the Pentax DA 10-17 fisheye zoom.

Me too. If I had that lens - you would find some examples on the web pages. I am a wide angle freak. And with a correction software I can get lenses that costs just a fraction of something that is rectilinear. I can even get lenses that is almost impossible to buy at all if I want rectilinear. That was the initial driving force behind writing the software.

I have a non sharp 8 mm fisheye. Looks fun - but a sharp one is on my wish list. Hmmmm ... Sigma makes a nice looking 8 mm. Coolest lens I have seen.

http://www.sigma-photo.co.jp/english/lens/wide/8_35.htm

But ... the 10-17 is actually way cooler. I don't think I can avoid buying it now

It says you have to tell it the focal length. Would you just do a few
of the possible focal lengths on the zoom? Says it doesn't like
raw.

This is the analyzer. And you only have to tell the focal length for old lenses where the camera does not know. And actually - in practice it is OK to not give it and accept the default value 0 for non zooms.

For the corrector you have to tell the focal length if you have an old zoom that does not tell the current focal length. But ... in practice this is quite hopeless. I would not recommend using this tool for this case. Fortunately, there are not so many really good old zooms. Old good lenses ar almost all fixed focal length.

Are all Pentax 6MP bodies the
same or would you have to recalibrate moving from DS to K100D?

They are the same. And if they were not - there is a recalculation JavaScript tool avalable in the manual. You only have to know the width of the sensors.

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OP John Bean (UK) Forum Pro • Posts: 18,035
Re: Proxel Lens Corrector

Roland Karlsson wrote:

But ... the 10-17 is actually way cooler. I don't think I can avoid
buying it now

Oh goody. I keep looking at one of those to use as an amazingly small rectilinear but have held off in the past because of the awkwardness of manual correction with PTLens. So now you really must buy it, make sure it all works well in the lens corrector and then I can buy one with confidence :-))

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Roland Karlsson Forum Pro • Posts: 27,539
Re: Proxel Lens Corrector

John Bean (UK) wrote:

Oh goody. I keep looking at one of those to use as an amazingly
small rectilinear but have held off in the past because of the
awkwardness of manual correction with PTLens. So now you really
must buy it, make sure it all works well in the lens corrector and
then I can buy one with confidence :-))

hehe ... that is actually one negative effect of owning a lens corrector - you can now buy lenses that you dreamt of using. You might get a serious LBA syndrome.

On the other hand - if you compare to what it costs to get al that lenses in rectilinier - you will save a fortune.

And actually - the Zenitar (at F/11) is also unbelivingly cool when you defish it. Just made a stroll in Stockholm in beautiful weather today taking some photos with the Zenitar.

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Enrico L Regular Member • Posts: 492
Re: Proxel Lens Corrector

It looks impressive.

Though I think the price is steep.

It has a plus for sure over PTLens (canvas extension) but then again also a minus (no CA correction).

But 34€ against 10/15/20$ is a difference.....

Do we know the future in what, if any upgrades are thought of, so further development of this plug in and what is the thoughts of the upgrade fee

Maybe it was beter to ask the furom of Proxel......

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Joseph Tainter Forum Pro • Posts: 10,177
Re: Proxel Lens Corrector

Thanks, John.

Each of your corrected images shows loss of contrast, at least on my lcd screen. Is that a consequence of these programs?

Of course, you could put the contrast back in.

Joe

OP John Bean (UK) Forum Pro • Posts: 18,035
Re: Proxel Lens Corrector

Joseph Tainter wrote:

Each of your corrected images shows loss of contrast, at least on
my lcd screen. Is that a consequence of these programs?

They do? Sorry I can't answer that. I can't see any difference. Anybody else see what Joe is seeing?

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