Is image quality loss after panorama normal?

[abruzzopat]

I'm noticing significant IQ degradation after stitching photos together using the panorama feature in Lightroom. I'm attaching two sample images. Both are 100% crops. You can see that the IQ is much lower after the panorama. These are RAWs with no processing other than the pano.

Is this expected? (I hope not!)

Thanks!

This is before pano:

And this is after pano:

[JohanElzenga]

Some image degradation is indeed to be expected. When Lightroom stitches the images, it must transform them in some way to get details to fit. Those are the three 'projections' you have to choose from. This looks more like the top image has been sharpened, and the bottom image has not, however. Here's the stitched image after smart sharpening in Photoshop.

[abruzzopat]

Thank you Johan. Just to clarify, I applied no sharpening or any other processing to either image. Of course Lightroom does process the RAW file with its default settings. I simply imported two CR2 files and stitched them.

I have attempted some processing (including sharpening) on the DNG panorama file, and while it can be improved, I am unable to come close to the sharpness I can achieve on the original files.

Almost all of my photography is for print, and I have been working on creating large panorama prints. With the loss of IQ from the panorama process in Lightroom, I'm not pleased with the final print I get, especially on metal prints where sharpness is really important.

Given your statement that "some image degradation is indeed to be expected", does anyone know whether other software out there is better at this than Lightroom?

Thanks again for your reply.

[abruzzopat]

Just trying one more time for another response... if this is expected IQ degradation from using Lightroom's panorama feature, does anyone know of another option?

Thanks again to the community!

[JP Hess]

Well, I don't know. I went out and shot a 21 image raw panorama today. I have highlighted approximately the area that one image would cover. Then I'm including a 1:1 snippet from the panorama. I also created the panorama using Photoshop and had about the same image quality. Personally, I'm reasonably happy with the quality. I know, the image itself isn't that great. But I was just experimenting.

[abruzzopat]

Thanks Jim. The 1:1 crop you show does look sharp. I guess the real test is, what does that same crop look like in the original image? Do you seem to lose IQ after doing the stitch?

[JP Hess]

Okay, here's a 1:1 crop of the single NEF file that includes that part of the panorama. It's a little sharper I guess. But I haven't applied any additional sharpening to the panorama, either.

[JP Hess]

I suppose if I want to push the sharpening it will make a difference. But I'm always concerned about overdoing it. This is from the panorama after adjusting the sharpening a bit.

The only trouble is, now we're starting to see some halos, and I don't like that.

[abruzzopat]

I see what you mean about the halos.

So let me ask you this: do you feel that there is a loss of IQ after stitching the photos with the panorama? I guess I'm just asking you to keep me honest... am I being too picky about losing some IQ when doing this?

Maybe I'm hoping for a perfect world where stitching shots together doesn't lose image quality. But I'm also wondering if there is other software out there that does it better.

Thanks again for your help... I really appreciate you taking the time to explore this.

[JP Hess]

I suppose there is always something that is better. You indicated that the panorama you created was from "sample" images. Have you tried creating a panorama from your own images to evaluate for yourself from your own work? It also depends on your equipment. I don't have any professional lenses. Do a web search for Gigapan if you really want to get into panorama images. You can spend $1000 or more for the device to mount your camera in. Then invest in some professional lenses to go along with the equipment and the software that comes with it and stitch images consisting of far more than 21 images and I suppose you can get razor-sharp, professional quality panorama images that would rival National Geographic work if that's what you're after. My lenses are consumer grade lenses. If I can get something as sharp as what I showed you today then I'm "reasonably" satisfied. The image you shared, especially the second one, was not very sharp, and I don't know whether you invested any time in attempting to sharpen it after you created the panorama. I'm happy with what I do. If that type of quality isn't good enough for you then I don't know what to suggest unless you want to really invest some money. That's something I'm not able to do.

I think the key to having truly sharp panoramas is pixel content as well as lens quality. The more pixels you can include the better your chances of having a higher quality image in the end. That's just my opinion, and it really isn't worth much. A few years ago I had my eyes set on obtaining some more professional quality lenses. But that goal has kind of gone out the window. Things have changed, and I'm not looking in that direction anymore.

[abruzzopat]

Ugh, I guess I misspoke. These are definitely my pictures, I was in Italy in March and spent a lot of time taking pictures to add to my collection of rural landscapes. I'm only "semi-pro" and try selling pictures at street fairs and craft markets. I do have good equipment, but not pro (my camera is a Canon 6D).

I was trying to be very open about the images being straight out of the camera... not sharpened. I wanted to point out the loss in IQ after doing the panorama and see if someone with experience could confirm whether what I was seeing was to be expected or maybe point me to a better method.

Another thing I should clarify... this is just two images I was stitching together... not 21. I'll take a look at what's out there for this. I'm not trying to be NatGeo... sorry if I came across as an ass.

[JP Hess]

Sorry that I misunderstood. I am far from being a professional. In fact, I'm an old, old retired guy turning 75 years old next week. I'm just an old goof off. My camera is far from professional, a Nikon D7100, 24 MP, and the lens I used was a 18-105 mm zoom lens set at 35 mm. I used aperture preferred set at f/8, autofocus enabled. I'm lazy, didn't want to bother with manual focus or manual exposure. That Gigapan that I referred to in my previous message, they talk about using even longer lenses and taking groups of like 50-100 images to create extremely high resolution panorama and not so panorama images. I don't know what to say about your demands or expectations. It's a question of what you expect and want. You have a good camera. Do you have a professional quality lens? Are you consistent with your camera settings? I am happy with what I get, and if it isn't up to the standard that you expect then I don't know what to tell you.

And just for interest sake, I'm using an old HP Pavilion computer, Windows 10, 8 GB RAM. It took the thing 6 min. to stitch that panorama. But I'm getting pretty slow myself these days, so speed doesn't really matter anymore.

[Joe Foe Toe]

abruzzopat, I suspect I speak for many when I say this is some of the stuff for which we live and breathe. An issue of IQ loss when stitching is hardly trivial. I'm interested in whether this part of your image might have been on an edge which i assume could be subject to more artifacts due to overlay. Or was weaker on one image etc. Having said all this, the sharpening done by JohanEl45 brought itpretty darned close to the original level.

[abruzzopat]

Joefry, I think what you mention might have a lot to do with it. I was just doing some very basic test shots and the IQ loss was not the same as my "real life" pics.

I can't do it right now, but I'll try to post complete images, crops, etc later in the week. I'm new to this forum, and I just want to say that I am very grateful for the help you guys are offering.

[Jao vdL]

abruzzopat  wrote

I see what you mean about the halos.

So let me ask you this: do you feel that there is a loss of IQ after stitching the photos with the panorama? I guess I'm just asking you to keep me honest... am I being too picky about losing some IQ when doing this?

Maybe I'm hoping for a perfect world where stitching shots together doesn't lose image quality. But I'm also wondering if there is other software out there that does it better.

Thanks again for your help... I really appreciate you taking the time to explore this.

The panorama stitch in Lightroom is very handy but it has some major drawbacks. One is a complete lack of control outside of the projection. This can indeed lead to IQ loss in the stitched panorama when you look at areas where lens distortion and projection would lead to major distortion. Also Lightroom is quite conservative in what resolution it renders the stitched panorama at (i.e. I haven't seen it render at the max resolution possible) and again you can't control it.

So bottom line is that if you care deeply about extracting the maximum detail, you need to use other software. My favorite is hugin which is free and open source and is superb quality wise but very hard to learn as you might have guessed. There are other pay-for tools that are easier and still give a lot of control. None of those tools will stitch in dng though like Lightroom does.

[abruzzopat]

Thanks Jao. I'll look into hugin. I'm new to pano so just need to see what's out there.

[Jao vdL]

The major commercial tools are PT GUI pro and Autopano Pro. I do a bunch of stitching even producing lots of fully spherical ones (e.g. Google Maps​) which I mostly do for fun as you can't effectively display them anywhere but online. Hugin is by far the best tool out there but also the most difficult to learn.

[JP Hess]

I am probably not going to explain this very well. Your second shot appears to be "about" the same magnification as the first one. If it was taken from the panorama image than it is of a much greater magnification than the original image. In my opinion, that would account for the difference in sharpness.

[JohanElzenga]

JimHess  wrote

I am probably not going to explain this very well. Your second shot appears to be "about" the same magnification as the first one. If it was taken from the panorama image than it is of a much greater magnification than the original image. In my opinion, that would account for the difference in sharpness.

I don’t understand that. The magnification could be different, but so is the panorama image. The panorama is much bigger than a single frame of it. The number of pixels should be roughly the same for both crops.