Lossy DNG File Sizes by ISO.

Fairly recently I discovered the magic of lossy DNG's. My stock photo library is ever growing. Though JPG's might really be enough for my archive, I've been keeping my raw files. RAW files take up lots of space. And RAW files can't typically keep user generated EXIF data in the file. RAW files keep their keywords and other metadata in a sidecar, that is if you regularly save the EXIF data to file.

So recently I've been converting all my RAW files to lossy DNG's.

After testing the highest ISO setting on the new-to-me A7R IV, I converted the files to lossy DNG's only to find a surprise. The very high ISO lossy DNG's were much larger than the original Sony RAW files!

Lossy ARW vs Lossy DNG full image sample

So I thought it would be a good test to shoot from the lowest to highest ISO, convert to lossy DNG and see where the file size savings invert. Here's the data as seen in the above screen shot:

ISO	Lossy Sony ARW Raw file size (MB)	Lossy DNG file size (MB)	efficiency
100	62	19.5	3.179487179
200	62	22.6	2.743362832
400	62	26.1	2.375478927
800	62	30.2	2.052980132
1600	from Lensbusters.com 62	35.7	1.736694678
3200	62	44.3	1.399548533
6400	62	54.6	1.135531136
12800	62	72.6	0.8539944904
25600	62.1	83.7	0.7419354839
51200	62.1	99.7	0.6228686058
102400	from Lensbusters.com 62.2	110	0.5654545455

At ISO 100, I saved 3x over the Sony ARW file. By 6400 file sizes were more or less even. At the highest ISO setting the lossy DNG took up roughly double the space of the original ARW file.

Lossy ARW vs Lossy DNG 100% image sample

This was just an exercise out of curiosity. For my, and I expect for most all of our workflows, the Lossy DNG offers a lot of savings in HD space. If you shoot lots of really high ISO shots, maybe it's not worth converting.

But for my library, lossy DNG's are great!

Comments

Linhof Serial Year List - Salomon Says

Recently I've acquired a few Linhof cameras. I got a 5x7 view camera from Oakland Museum's White Elephant Sale. Later I stumbled upon a Color Kardan 90 Jahre Jubalaeum edition on Craigslist. And more recently, I found a "baby Technika" 2x3 (6x9) at Oakland's East Bay Depot for Creative Re-use. Not knowing much about Linhof large format cameras, I tried getting more info online, and came across a strange thread on the Large Format Photography Forum . Basically on this thread various Linhof owners ask a guy named Bob Salomon what year their Linhof was made. And the thread is over 100 pages long! Sifting through that thread is mindnumbing. Why Bob doesn't just publish the list of serial numbers is beyond me. Maybe it's just nice to feel needed. So I started compiling a spreadsheet of the serial numbers and the answer Bob gives. If you don't feel like spending a couple days reading this thread to get a hint as to the age of your Lin

Should I ditch my Sony a6500 for a A7r IV?

Recently, I bought a Sony a7r IV. The main reason was for stock photography. The high resolution along with improved focusing and biggish buffer would allow me to make better people (and other) stock photos for my various stock endeavors. The Sony system has treated me well. I own two A7r II's for stock and other work, and two a6500's for event photography. The A7r II's aren't ideal for events for a couple reasons. The focus tracking is pretty good, but maybe not enough for fast paced people on stage. Another reason is that silent shooting is only available on single shot mode. And (admittedly a first world problem,) the files are much bigger than needed. Well, the last problem, too big files isn't an issue with the A7rIV if you use it in APS-c mode. The files are effectively the same size as the a6500: 24 mp. Focus with the IV is even faster and more effective than the very capable a6500. And with those smaller files, the IV has no problem with buffer overflow. So

Long Daylight Exposure Chart: Kentmere 100

Ultrafine/Kentmere 100 Reciprocity Test-Camera: Fuji G617, Film Ultrafine (E)Xtreme 100, ND-9+red @ f22 140 seconds If you are interested in long daylight exposures, you may have run in to the same problem I have. Say you have your camera all set up, the clouds are whisping by, and you want to get that long daylight blur thing going. You figure a 30 second exposure (approx.) would be ideal. Well how do I get there? I've got a bunch of filters: a 4 stop ND, a 9 stop ND, as well as a red, yellow, and orange filter. It's mid day and my meter reading says 1/125th @ f16. I start counting with my fingers: -1 stop = 1/60th, -2 stop = 1/30th, and so on. So then I get down to 4 seconds with my darkest ND filter. If I stack both my ND filters, I get down to 30 seconds where I wanted to be. But wait! That's without reciprocity corrections. Great if I had Acros for film. But I don't and it's being retired soon, so I wont have access to it at all. What I ended up makin

Lensbusters.com

Search This Blog