13 replies to this topic

[adamhanlon]

Hi all,

My typical workflow involves using the lens correction profiles in the develop section of Lightroom 4. During the testing of the D800, using the Sigma 15mm lens and a ZEN 230mm dome, I noticed that the corners on the images were very soft.





I put this down to a hardware issue and started experimenting with extensions on the dome to overcome the softness.

However, I was looking at the images in LR and noticed that when i removed the lens correction, the softness/distortion went away!




The Sigma 15mm lens profile seems very off!

If you are getting weird soft corners with this lens, this may be a possible reason! Saying that, perhaps this is something that is happening with my installation of LR, has anyone else found anything similar?

Adam

[Timmoranuk]

Hi Adam, have you tried creating a custom lens correction profile?

[Autopsea]

I normally do it manually, so I can see at what point it start creating softness/distortions.

[kmo_underwater]

Have you tried the lens profile on any topside photos?

[adamhanlon]

I will play with manual correction both underwater and on the surface. I used to have a plug in called PT lens, I'll try it too to see if I get any better results.

Adam

[scubamarli]

Also, Adobe usually uses only the most recent version of a lens for the profile. I don't notice softness when applying the correction, but sometimes I prefer the look without.
Cheers,
Marli

[jonorunde]

I have seen the same with D700/Sigma 15
It looks like the "correction" tries to make something that looks like a non-fisheye-image, which is not what I wanted at all.
Basically I stopped using it, both over and under the surface

jono

[Aquapaul]

I second the D700/Sigma 15 FE, but with Lightroom 3.But topside it seams to work great.

[Paul Kay]

Adam

I'm not familiar with Lightroom (I use Photoshop) but what exactly is this lens correction trying to achieve - a rectilinear image from a fisheye shot? Domes create distortion (because they are just a simple spherical lens placed in front of the sophisticated camera lens) as well as the lens, so an above water correction may well not work with the lens when its used behind a dome underwater because of the additional distortions added by the dome. These distortions will almost certainly vary depending on the subject distance and consequent focus setting, and additional distortions and aberations will occus as you focus closer. [Even with flat ports the amount of correction of chroma needs varied adjustment for different focussed distances so I'm sure the same (but worse) applies to domes too.]

[scubamarli]

Yup, upon looking closer, it's doing the same thing for me, with my old D200 and the older version Sigma 15mm FE. I just won't use it.

Cheers,
Marli

[John Bantin]

Lens correction? I just go out and take pictures with it. Nobody's suggested my pictures needed lens correction (a lot of other corrections, maybe!).

[scubamarli]

I was working on some shots from Salt Pier, Bonaire. I didn't like the distortion on the pilings. The Lens profile default over-corrected. I pulled back on the distortion slider and that seems to do the trick. Unless there are obvious parallels in the photo, I would leave the lens profile off in this case.

Cheers,
Marli

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[stewsmith]

I think thats a great example of when lens correction is needed Marli.

stew

[rtrski]

Yes, good example of where fisheyes aren't nice and a rectilinear WA is nicer. I do understand that rectilinear WA have their own issues with complex distortion and dome pairing...but the former is subtle and the latter seems solveable. So far, I still prefer trying to shoot with the 8-16mm and haven't even attempted taking the 10mm FE under.

I was going to post that I bet the lens correction was assuming normal optical use in 'air' and the extra air/water interface distortions behind a dome were defeating it, but I see I got beaten to the punch on that....

Edited by rtrski, 28 August 2012 - 06:59 AM.