D-Lux 4 from a D-Lux 3 users perspective; Lightroom via DNG; barrel distortion

[macgarvin]

Advertisement (gone after registration)

Hello Howard

 

Sorry to hear about your engine - blame it on the fairies, when they take a car the wheels don't touch the ground!

 

On the wider coverage of the lens - aha! I hadn't thought about that. So 4:3 and 16:9 would go into the usable areas that I found within the C1 .dng 3:2 image up at the top of the post?

 

For the data carried over in the RAW format - if panasonic/leica have added a data field 'barrel distortion correction factor', it's still a bit curious is it not? You'd think the raw files from C1 and Adobe would come about identically corrected for barrel distortion using just that data - why would someone outwith of p/l decide 'we think the optimum correction for the RAW is different from the default?

 

And is including a data field for chromatic aberration correction non-trivial - ie would it have to allow for f as well as focal length - I have no idea, curious if anybody else does!

 

BTW re. the link to photos taken with low sun/ into sun in my last post. What I should have added was that I was doing considerable raising and / or lowering in the shadows and highlights without the quality breaking down unacceptably - the dynamic range on the D-Lux 4 seems to be very good.

[ho_co]

Mac--I'm calmer today. Thanks for the calm response to my rudeness. My engine's failure is no excuse for my response to your legitimate questions. My apologies.

 

 

... For the data carried over in the RAW format - if panasonic/leica have added a data field 'barrel distortion correction factor', it's still a bit curious is it not? You'd think the raw files from C1 and Adobe would come about identically corrected for barrel distortion using just that data - why would someone outwith of p/l decide 'we think the optimum correction for the RAW is different from the default?

Capture One gives you full correction in its TIFFs (which you can work from if you want), but the two companies write their DNGs differently: Phase One generates standard mosaicked DNGs. Adobe writes linear DNGs, provided for in the DNG spec but not previously used, and as Sandy says, not recognized by most software. That's why Adobe had to re-write ACR. There's no place in the mosaicked form for these data, but there is in the de-mosaicked form.

Why choose a not-fully-corrected output? My guess is: First, the fully-corrected version in many cases doesn't look as good (so-called 'wide-angle distortion'). (I have a perfect example but can't figure a way to upload a usably sized image of the TIFF.) Second, the file is already fully corrected for most aberrations and easy to correct for distortion, as you've done above. Good compromise.

 

And is including a data field for chromatic aberration correction non-trivial - ie would it have to allow for f as well as focal length ...

It's not trivial. I don't know, but I don't think CA varies with aperture. The Nikon D300 requires focal length input and isn't as sophisticated as the D-Lux 4's adjustments. The D-Lux 4 has the benefit that it has only a single lens, so corrections can be optimized. Nonetheless, its images seem to me adequately but not perfectly corrected. This is new territory in lens design, and I'm sure there will be further developments.

 

On the wider coverage of the lens - aha! I hadn't thought about that. So 4:3 and 16:9 would go into the usable areas that I found within the C1 .dng 3:2 image up at the top of the post?

I've forgotten the source of this diagram, but I think it helps to visualize the design.

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

[macgarvin]

On a scale of one to ten it didn't register - you should see (perhaps you know!) the sort of things that peer reviewers say when reviewing scientific articles safely behind the cloak of anonymity! - absolutely no need to apologise for anything.

 

Will be interesting to see what is in the white paper (data fields) for the new Adobe RAW spec, and also how Apple deal with this (if you have a mac, that is).