LR and lens distortion correction

[stump4545]

Advertisement (gone after registration)

if a portrait suffers from barrel distortion does the correction in LR resolve it 100% or does it just make it better?

 

is there any image quality loss in using the distortion correction?

 

 

i wish aperture3 would have it built in.

 

thanks

[Advertisement]

The Leica Q3 is available for pre-order at B&H Photo Video and Adorama

[hoppyman]

If you want you can adjust the amount of lens correction in LR and save it as a pre-set. The corrections for M lens are not large in any event. I don't bother at all with files from mine.

But perhaps you are asking about perspective effects from shooting at close range with shorter focal lengths?

[stump4545]

yes i am shooting at close range under 8ft with a 24mm or a 21mm.

 

does LR correct these distortions 100% or just make them better?

 

any loss in image quality by using lens correction module?

 

thank you kindly.

[Jeff S]

This Julianne Kost video may provide some useful info regarding lens correction and perspective control with LR 4. See the first 4 minutes or so.

 

Jeff

[hoppyman]

There are several different topics in that question

I will have to be careful with definitions and explanations or there will be a slew of responses correcting me

If you shoot with wider lenses at closer ranges objects closer to the camera look larger in proportion to further objects. The classic example being a larger nose in a portrait with a shorter lens at minimum distance.

 

The lens corrections now available in LR are not designed to correct that out. They are for global characteristics of a lens rather than perspective changes.

The tool is simpler than the equivalent in PS since it is not meant for fixing keystoning for example.

 

When you enable profile corrections in the lens correction panel you can choose any available profile (whether it makes sense or not) from any brand and apply an auto or manual distortion and/ or vignetting correction and set anything you like as your default..

 

So have a play with your specific examples is the best way to discover if you can change the files as you want. There is no penalty in that the edits are always non-destructive.

 

Regarding image quality loss, the answer is technically yes...but

By definition you must lose some original information but that does not always mean that this is significant or outweighs the benefits.

For example even the high end professional SLRs will routinely write corrections into the original raw information in camera and for Four thirds/MFT systems this is an essential part of the image chain. In principle Leica Camera tries to make the corrections in lens design rather than in camera.

Nevertheless vignetting is managed in camera in any case. Taking that specific case, if the corners are having an effective increase in exposure you are losing some range there if you like and potentially increasing noise.

The key thing to keep in mind is whether the change is practically significant.

 

yes i am shooting at close range under 8ft with a 24mm or a 21mm.

 

does LR correct these distortions 100% or just make them better?

 

any loss in image quality by using lens correction module?

 

thank you kindly.

[stump4545]

thanks to all

 

thanks for the link Jeff, it was really helpful.

[hoppyman]

Advertisement (gone after registration)

That link from Jeff S is excellent, as is all of the instruction from Julieanne Kost. It also pointed out what I had missed completely thus far. That is the manual options for perspective correction which duplicate the functions that the PS version has. I was not even aware that those were there in LR.

[01af]

If a portrait suffers from barrel distortion...

A portrait never suffers from barrel distortion. Architectural pictures somestimes do, and in rare cases, landscapes.

 

 

... does the correction in Lightroom resolve it 100 % or does it just make it better?

If the lens was focused at or near infinity then the correction will be perfect or near-perfect. However as the lens distortion changes with focus distance (typically getting worse at close distance, except with macro lenses), the correction usually will under-correct the distortion at portrait or close-up distance. That's why there's a slider to adjust the amount of correction to more or less than 100 %.

 

But then, as I already said above, portraits don't suffer from barrel or pincushion lens distortions. I guess you're confusing these with perspective-related distortions which are a completely different thing.

 

 

Is there any image quality loss in using the distortion correction?

In principle, yes—but it's entirely negligible for all practical intents and purposes. So don't worry about that!

[stump4545]

do better brands of 24mm and 21mm (ex leica) exhibit less perspective distortion then lesser brands or is perspective distortion really only a function of how much you angle your lens during a shot?

[Dougg]

do better brands of 24mm and 21mm (ex leica) exhibit less perspective distortion then lesser brands or is perspective distortion really only a function of how much you angle your lens during a shot?

Perspective distortions like converging vertical or horizontal lines are a fact of nature, dependent on where you're standing and which way you're looking or shooting. Any lens of any focal length will show this, not an optical fault. Just more obvious with wider lenses...

 

On the other hand, when you speak of optical distortions like barrel or pin-cushion distortion, these are the result of lens optics. Lenses made for macro shooting or printing processes are generally made rectilinear, eliminating these characteristic distortions. There are tradeoffs in lens design; gain something, lose something. Even the best lenses may show a bit of barrel distortion, generally acceptable to some extent. Usually hard to see unless you have a known-straight line running near and parallel the the frame edge.