jpg vs dng

[Rubik]

This is a really hard subject to discuss on this forum. I can't show you my .dng files without converting them to .jpg. In fact, I've found that the viewing software has a significant impact on the quality of the picture that I see. For example, in Windows 10, I have "Windows Photo Viewer" and "Photos". I can also look at photos in Corel Paintshop Pro. Each of these give significantly different results. And, my "Raw Photo Editor" won't even open the Yuneec .dng files.

I took a series of photos of my backyard with the CGO3+ on a cloudy day. Photo color settings used were Natural, Gorgeous and Raw. File types were .jpg and .dng. That makes 6 different combinations. All photos were taken with white balance on Sunrise/Sunset and auto exposure. The .jpg photos varied in file size from 5-9 Mb depending upon the color mode. Gorgeous files were the largest and Raw were the smallest. The .dng files were all 23 Mb. All .jpg images were 12 Mp (3000x4000 pixels) and .dng images were a tad smaller at 11.9 Mp. The Raw images were color deprived and the Gorgeous images were overly colorful.

I zoomed into each photo about 8x on my 4k computer monitor to see what's there. The "Photos" program did a lot of unwanted smoothing of the images compared to "Windows Photo Viewer". In Corel PaintShop Pro, images were much noisier at that magnification compared to the viewers. So, I based my comparison on "Windows Photo Viewer".

If the .dng files had more information in them (based on the huge file size), it was sure hard to see it. Aliasing was about the same. Image noise was about the same. Where lighting was poor (shadows), the .jpg compression occasionally muddied up some details. The real surprise was how good the Raw/.jpg file looked. They have the smallest file size and the smoothest image but with a little post processing, they can be made to look pretty good. After much comparison, I was most happy with the Natural/.jpg files.

This is really frustrating because, like the Heisenberg Uncertainty Principle, you can't observe the image without it being changed in the process. But, based on what I could see, I don't understand why some people are so enamored with the .dng file type. Comments?

 

[Rayray]

I use 2 good (free) programs on my W7 and W10 PCs. Irfanview and VLC. Irfanview will handle .dng pics, and VLC is great for videos.
Happy flying.

 

[Tuna]

The dng files are uncompressed and unprocessed (apart from colour balance - controlled by the Natural/Gorgeous/Raw setting).

The .jpg files have two things done to them (1) there is some sharpening applied and (2) they are compressed.

The sharpening settings and compression settings have been decided by Yuneec to be the 'best' for normal photography. And I have to agree - most of the time they work really well.

However, the side effect of sharpening in particular is you get noise added to some areas of the image, and some edge effects. If you're really concerned about getting the absolute best out of the camera, you'd want to use Unsharp Mask in a good photo program and adjust the parameters to get decent sharp edges, and smooth areas between them without losing texture. Sharpening an already sharpened image is a recipe for disaster, so you have to start from an unprocessed image. So if you intend to post-process your images and are really happy about using advanced photo tools - DNG is the way to go. Otherwise, there is absolutely nothing wrong with JPG for the CGO3+.

By comparison, the DNG image will look 'blurred', but there is actually more information in that blurred image than there is in the sharpened image you can produce from it. However, to our eyes a nice crisp sharpened image looks as though it has more detail.

As an aside, I think Windows Photo Viewer tries to make the picture look 'nice' on your screen. PaintShopPro will be showing you the image as it is recorded, which may look noisier.

 

[BroVari]

Photos in raw .jpg cannot even be compared to the ones made in raw .dng format. In my humble opinion the .jpg is unusable to me while .dng is very flexible and has huge amout of detail. I am using Lightroom to postprocess the photos and the outcome of that postprocessing is just outstanding in comparison to .jpg. (especially when you take into consideration that there is so much bad opinions about the CGO3+, with which I obviously don't agree). I am photographing in the jpg + dng mode as soon as this option was added with the firmware and when Lightroom imports all the photos from the card the difference between those two formats is clearly visible right away.

 

[Ty Pilot]

Something to consider is; all monitors are not the same. The difference between a basic monitor and one that is capable of displaying images at the highest quality with correct color is pretty vast. I have a work computer that I built solely for video and photo work and another that I use for daily stuff online and so on. When outputting a project and seeing it side by side on the two systems there is a distinct difference. My workflow for photography is to Use Adobe DNG converter, then into Photoshop, then to final output. If I take a DNG through this process and output it as a JPG it will be in the neighborhood of 14 to 17 MBs and, side by side with the stock JPG (on any setting) its not hard to see that the DNG original has a clear edge. Also the DNG does not change with the camera settings between Gorgeous, Natural and Raw, those are just three different presets that are applied to the JPG.

 

[Rubik]

I use 2 good (free) programs on my W7 and W10 PCs. Irfanview and VLC. Irfanview will handle .dng pics, and VLC is great for videos.
Happy flying.

Yes, I already have and use VLC. Good video viewer.
Just downloaded 64-bit Irfanview and a plug-in package. Two things: First, the Image Information shows my Yuneec .dng file as 2000x1500 (3.00 MPixels) with no compression. Second, when zoomed in about 8x, the image has much more color noise than the .jpg images. Does this match your experience?

 

[Eagle's Eye Video]

Two factors to consider... one we have no control over, but one we do.

We do not have control over to what degree of compression, the JPG settings are.
IMHO, the compression puts it in the high quality category, but not a minimum
compression ratio... which is usually a file size around 35% of the uncompressed
file. So a maximum quality JPG would save at about 8-10MB, based on a 23MB
DNG file.

Depending on which format you want to work with, you can adjust the image
to your liking in terms of sharpness with the "Get Sharpness" command.
Also note, that making this adjustment will equally apply in both photo
and video modes.

Connect to the CGO3 through your wireless connection, whether on a smartphone
or your home Wifi. Once connected, type this into your web browser:

http://192.168.42.1/cgi-bin/cgi?CMD=GET_SHARPNESS

It should return a value of what the sharpness is set at for your camera.
The default is at "6".

To change it, type this into your web browser to change the value,
by changing the end value of the command line, 1 thru 10. The higher
the number, the greater the degree of sharpening in-camera.

http://192.168.42.1/cgi-bin/cgi?CMD=SET_SHARPNESS&value=5

 

[Rubik]

Photos in raw .jpg cannot even be compared to the ones made in raw .dng format. In my humble opinion the .jpg is unusable to me while .dng is very flexible and has huge amout of detail. I am using Lightroom to postprocess the photos and the outcome of that postprocessing is just outstanding in comparison to .jpg. (especially when you take into consideration that there is so much bad opinions about the CGO3+, with which I obviously don't agree). I am photographing in the jpg + dng mode as soon as this option was added with the firmware and when Lightroom imports all the photos from the card the difference between those two formats is clearly visible right away.

Thanks. I just installed a trial license of Lightroom. I can see that it will take a while to get useful results. But I already see that the color noise that I see in the magnified .dng files can be easily corrected in the Noise Reduction section. What settings should I be using to get a clean .dng import and good .jpg export?

 

[Rubik]

Wow! Fiddling with Lightroom a bit more, I'm already getting results processing a .dng file that are better than anything that I've seen with .jpg. How is that possible when both files have the same number of pixels? More color depth on each pixel?

 

[Ty Pilot]

During the compression into JPG, there is a lot of data that once compressed is never to be regained, and is lost. This happens mostly in areas of shadows and highlights. As an example; if you're shooting a horizon shot on a bright sunny day, the sky can to be slightly overexposed while the ground detail is slightly under exposed. In a JPG, the compression tends to merge the subtly of the white clouds and a blue sky into a milky-white blown out sky while the ground looks okay but has very low detail in the shadows. Even though the CG03+ is not a pro level camera, it captures more detail than the JPG's it produces will ever have but the DNG it produces has all of the detail it can capture; assuming the operator properly exposes the shot. A DNG allows one in post, to preserve and enhance these details in the highlights and the shadows so the image has a far wider dynamic range than a jpeg is capable of.

 

[Tuna]

Yes, I already have and use VLC. Good video viewer.
Just downloaded 64-bit Irfanview and a plug-in package. Two things: First, the Image Information shows my Yuneec .dng file as 2000x1500 (3.00 MPixels) with no compression. Second, when zoomed in about 8x, the image has much more color noise than the .jpg images. Does this match your experience?

I'm nervous of Irfanview - I seem to remember some other users found that it gave incorrect information for DNG files and showed them at very poor quality.

 

[Ty Pilot]

I thought I would share an example of where a DNG shows its potential, so I set up a shot inside my garage shooting out across the road with camera intentionally tilted up to the sky. It was a sunny day so I set the ISO at 100 and exposure set to about 1/800 to properly expose the colors of the blue sky, WB was also set to "Sunny" and the JPG setting was "Gorgeous".

The original JPG - at full resolution is 2.89 MB at 12 Mega Pixels (3000 x 4000).
The raw DNG file is 22.9 MB at 11.944 Mega Pixels (3992 x 2992).

The full size, color corrected and finished PNG is too large to post on this forum at 20.9 MB's! So I took the unaltered "Gorgeous" JPG and the corrected PNG and reduced both using Photoshop's Bicubic reduction to a width of 1200 pixels and the corresponding height with no compression. Shown Below.

JPG vs DNG - Side by Side

As you can see with the sky properly exposed, all of the shadows in the JPG are crushed with very little detail. Notice the edge of the garage door opening and the tree to the right; very little detail and color and very dull. Also notice the light on the bottom of the Typhoon, no color and in general there is a magenta cast to the entire image. Now if one were to brighten the dark areas you would begin to blow out the highlights in the sky and loose cloud detail. The DNG on the other hand still has all of the details of the sky but you can see how much of the shadow detail can be regained, garage door edge, tree to the right and the color of the light on the arm of the Typhoon is now revealed. These images don't do the full size finished picture justice but hopefully shows where a DNG allows to to get the most out of the CG03+

JPG


DNG

 

[FlushVision]

Nice comparison. The quality of the DNG image is astounding.

 

[Ty Pilot]

Thanks FlushVision, I am also amazed at what you can pull out of these images once you know what to look for.

 

[Rubik]

Ty, I see what you are saying about details in the light and dark areas. I'm sold.
However, your .dng/.png image seems to me to have a green tint, especially noticeable in the gray cement pavement. I've checked it with both of my monitors. I'm sure that is easily corrected.
Thanks for posting the comparison.

 

[archybaker]

There is one other reason to prefer dng over jpg. Every time you open and close a jpg, it compresses the image. Over time, that will degrade the image (it takes a fairly high number of closures before the image degrades enough for it to be visible to the naked eye). dng is considered a lossless format (along with RAW and TIFF formats) because it doesn't degrade. The museums that I have worked with that accept digital photographs for curation request images in a format other than jpg for this reason.

Unfortunately, most of the free photo viewing software apps can't read dng or raw format.