entusiasmo
MobiStarter
- Real Name
- Mauro
@Stackables thank you so much for you clarification!
So, do you think it's like the compression quality isn't (for some reasons) setted to 100% on IOS7?
Problem with streaked vertical lines
- Thread starter maktub77
- Start date
So, do you think it's like the compression quality isn't (for some reasons) setted to 100% on IOS7?
It has nothing to do with iOS7. It depends on what compression quality the app developer opts for, which in most cases would be low in the interest shorter processing times and smaller file sizes.
Our app, PhotoFusion, gives users control over JPG compression quality. We'll run a test when we have some free time later today at 100% quality to determine whether these lines appear or not, but I doubt they will.
Mikeraboy
MobiLurver
- Real Name
- Michael Raboy
It's great that a developer has given input, but I am confused. If I open in from an app that accepts a PNG or Tiff file, but does not save as such, then re save in a file that saves PNG's or Tiff's then aren't the saved files actually PNG's and Tiffs and are lossless. When I do that I don't get the vertical streaks or change in color. Another point, is that if you compare a jpeg to a Tiff or PNG before editing they have more data and you can see the difference. I have observed that, but others have taught me this. Anyway, thanks for your input and we have another interesting discussion. We need the developers to understand that there is a market, maybe small, that would like to save as tiffs. 645pro, Filterstorm, Leonardo, CortexCam, KitCamera all do it. You will be doing it and I would like to see it in iColorama and Snapseed.
Ok, so I conducted the test in PhotoFusion running iOS 7 at 100% compression quality and here are the results. I, for one, didn't notice any deterioration in quality.
Original:
After 10 saves no editing
Images are not necessarily passed on in the same format. It's completely up to the developer to decide what format to support. For instance, an app might not support PNG format for saving but might support it for the "open in" option. It depends.
Also, JPG files at 100% compression contain about 75% of the data available in PNGs simply because they don't carry the alpha component (rgba) that supports transparency.
Mikeraboy
MobiLurver
- Real Name
- Michael Raboy
How do we know what the app supports? By the way I am always extracting something from an image and placing it in another. I spent the whole day today trying to do it in iColorama with little success,. I just purchased Photofusion and watched the video. I am going to try it, maybe the answer I am looking for. Back to the subject, beautiful photo and your app passed the test! ....... And good info.
Thanks, happy to be able to shed some light on the situation.
By the way, the default compression quality in PhotoFusion is set at 80%. Be sure to increase to 100% in settings.
I'll be very interested to see if your results match mine.
By the way, the default compression quality in PhotoFusion is set at 80%. Be sure to increase to 100% in settings.
I'll be very interested to see if your results match mine.
Mikeraboy
MobiLurver
- Real Name
- Michael Raboy
I will try it, but my photo won't be as nice as yours. I call it a"test" photo. You have cleared up why so many very good iphoneographers use jpegs. If the quality is almost the same look at the speed and the memory saved. Having developers on MobiTog has sure helped me understand what is going on and how to get the best from the apps that we are using.
Thanks again.
Thanks again.
- Real Name
- Jennifer Sharpe
ok this is really interesting - it comes down to the apps then... but why doesn't this happen in iOS6 and before?... with apps from the same developers? it's not something people even thought about before iOS7, and it appeared to be something people didn't need to think about because these problems didn't happen. I'm running iOS6 on iPhone4 and I've never had these problems with jpegs no matter what I've done with them in any app.
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- Real Name
- Jennifer Sharpe
and does it happen only with app use, or native camera too?
Looks great! Glad your results match mine!
Yes, a JPG with 100% compression is almost a third the size of a PNG, still it's exponentially larger than JPG with lower compressions. For example, it's 3 times larger than a JPG with 80% compression.
Can't comment on what other apps are doing, but we haven't experience this issue with our apps as demonstrated by the attached images.
- Real Name
- Rog...
- Device
- iPhone 13 Pro
@Stackables - Thank you for joining in the discussion Sam, it is invaluable to us, as users of the many and varied Apps available to Mobile Photographers, to have the insight and views of the Developers of those Apps, especially when issues like streaking and purple haze are experienced and most of us will not have a clue why, what, when or how the blight affects us...
Now that you have joined the fray and added some valuable information, I am wondering if we might entice input from @Mike Hardaker of 645 Pro fame, Teresita @iColorama, @Tai Shimizu of Filterstorm, @Darren@RI of Monokrom and other App Devs, who may have a view, to join in and comment on the experiences described here? ...
I wonder if we can crack this one once and for all as it does seem to be making MobiMembers wary of iOS 7 for no real reason other than a misunderstanding of the effect Apps have on iMage quality and outputs...
Ok, so my inquisitive mind has compelled me to come up with 2 simple experiments that will put some of the above issues of contention to rest!
EXPERIMENT 1: This experiment is designed to determine what format images are exported in using the "open in" option.
TEST APP: Snapseed, simply because someone pointed out that it doesn't support PNG format for saving.
CONTROL APP: Dropbox, because it supports all image formats, as far as I know, and doesn't alter them in any way.
Ok, so here's what I've done. I've loaded a PNG image into Snapseed and then opened it in Dropbox using the "open in" option. And guess what! Snapseed passed the test! The image retained its PNG format. I ran the experiment again with a JPG image and got the same results. See screenshots:
EXPERIMENT 2: This experiment is designed to determine what compression quality is applied to JPG files when saved.
TEST APP: I'll continue my tests on Snapseed.
CONTROL APP: PhotoFusion, because it provides users control over JPG compression quality.
So here's what I did. I loaded a test JPG image into PhotoFusion and saved it at 100% compression quality. I then opened the saved image in Snapseed and saved it to my camera roll.
The PhotoFusion saved JPG 100% compression quality image came out to 6.5MB while the Snapseed saved JPG came out to only 2.2MB. So I figured they must be using a lower compression quality. Therefore, I again loaded the original test image into PhotoFusion and this time saved it at 90% compression quality which resulted in a file size of 2.0MB, which I thought is close enough and stopped here. You could, of course, continue to decrease JPG compression quality in PhotoFusion by 10% increments until you get a matching file size. See attached:
EXPERIMENT 1: This experiment is designed to determine what format images are exported in using the "open in" option.
TEST APP: Snapseed, simply because someone pointed out that it doesn't support PNG format for saving.
CONTROL APP: Dropbox, because it supports all image formats, as far as I know, and doesn't alter them in any way.
Ok, so here's what I've done. I've loaded a PNG image into Snapseed and then opened it in Dropbox using the "open in" option. And guess what! Snapseed passed the test! The image retained its PNG format. I ran the experiment again with a JPG image and got the same results. See screenshots:
EXPERIMENT 2: This experiment is designed to determine what compression quality is applied to JPG files when saved.
TEST APP: I'll continue my tests on Snapseed.
CONTROL APP: PhotoFusion, because it provides users control over JPG compression quality.
So here's what I did. I loaded a test JPG image into PhotoFusion and saved it at 100% compression quality. I then opened the saved image in Snapseed and saved it to my camera roll.
The PhotoFusion saved JPG 100% compression quality image came out to 6.5MB while the Snapseed saved JPG came out to only 2.2MB. So I figured they must be using a lower compression quality. Therefore, I again loaded the original test image into PhotoFusion and this time saved it at 90% compression quality which resulted in a file size of 2.0MB, which I thought is close enough and stopped here. You could, of course, continue to decrease JPG compression quality in PhotoFusion by 10% increments until you get a matching file size. See attached:
Mikeraboy
MobiLurver
- Real Name
- Michael Raboy
So, higher quality jpg matters and remember that original post in this thread was photo taken with higher resolution 5s . If you are using Snapseed the it would be smart to save as a png. Now we need to hear from other developers as Rog has commented!
Yes, based on the above test, if you're using Snapseed and would like to preserve the PNG format you must open it in another app because the minute you save it to your camera roll it's converted to JPG.
So one could easily do the above tests to determine how images are handled by apps.
- Onsite
- Project Page
It's conv
It's converted to JPG even if opened in another app. To test this, open a TIFF file in SnapSeed, then use "Open In..." to open in Big Photo. Check the photo info. It's JPG.
- Real Name
- Tai Shimizu
I haven't read the entire thread through carefully, so forgive me if I'm missing something.
My guess is this: The apps in which this issue was found are using the same method to share to the camera roll, I'd guess
UIImageWriteToSavedPhotosAlbum, as it takes a uiimage, and NOT a file. This method allows the OS to apply the compression and decide on compression quality. Other methods which take a file, simply maintain that file. Apple probably lowered the JPEG quality on this method to save space for users, and for photo stream.
My advice: Upgrade to iOS 7 immediately! Filterstorm Neue is only available on iOS 7, and you should all be using it! It does not suffer from this issue as you can always save to Tiff, PNG, or Jpeg at arbitrary quality.
If you upgrade and still want to use the affected apps alongside Filterstorm Neue, using the open in function to send the image back to Filterstorm Neue and then saving from there seems like a wise course of action. Don't worry, I'll forgive you for using other apps.
My guess is this: The apps in which this issue was found are using the same method to share to the camera roll, I'd guess
UIImageWriteToSavedPhotosAlbum, as it takes a uiimage, and NOT a file. This method allows the OS to apply the compression and decide on compression quality. Other methods which take a file, simply maintain that file. Apple probably lowered the JPEG quality on this method to save space for users, and for photo stream.
My advice: Upgrade to iOS 7 immediately! Filterstorm Neue is only available on iOS 7, and you should all be using it! It does not suffer from this issue as you can always save to Tiff, PNG, or Jpeg at arbitrary quality.
If you upgrade and still want to use the affected apps alongside Filterstorm Neue, using the open in function to send the image back to Filterstorm Neue and then saving from there seems like a wise course of action. Don't worry, I'll forgive you for using other apps.
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Tai, you're probably right, the UIImageWriteToSavedPhotosAlbum method or other Assets Library methods that take an image instead of data might very well be responsible for the discrepancies witnessed between iOS 6 and 7. Though, I can't for the life of me understand why developers would use such methods!!
The "Open in" protocol (documents interaction method), however, always takes in data, so it's the responsibility of developers to support certain file formats and set JPG compression quality. As a result, files might have already experienced a certain degree of compression/degradation before even being transmitted.
PNG format was preserved when opened in Dropbox as can be seen in the screenshots. haven't tested on other apps or for TIFF.
- Real Name
- Jennifer Sharpe
This is what I intuitively suspected, because this problem does not happen on older devices with an older iOS:
"My guess is this: The apps in which this issue was found are using the same method to share to the camera roll, I'd guess UIImageWriteToSavedPhotosAlbum, as it takes a uiimage, and NOT a file. This method allows the OS to apply the compression and decide on compression quality. Other methods which take a file, simply maintain that file. Apple probably lowered the JPEG quality on this method to save space for users, and for photo stream."
The last sentence says everything - "Apple probably lowered the JPEG quality on this method to save space for users, and for photo stream" - and therefore it IS a problem with iOS7. This would probably be why there is so little response (and interest?) in resolution on the part of Apple for this problem. Though why they're not communicating with developers to spread the word to their consumers, and help them make good choices to get past this issue, is a mystery.
I will note the advice of the developers here and make sure I get the upgraded/and or the new versions of the apps above, particularly if this problem continues, when I get my new device and iOS (in about a month).
This is an invaluable discussion. Thank you, those of you who are developers, for enlightening us!
- Real Name
- Jennifer Sharpe
Brilliant! This is so interesting, thank you for enlightening!
Sorry if I come across as a big Apple proponent, but I don't think Apple is entirely to blame for this mishap. Remember that Apple's primary customer base has little interest in or knowledge of photo quality, formats, etc. and are probably more concerned with disk space and photo sharing. So to be fair, I believe the onus should full on developers, particularly those of professional editing apps, to employ methods that preserve photo quality/integrity especially since many are available to them through iOS's extensive SDK.
So users should speak out and demand these improvements.
- Real Name
- Jennifer Sharpe
you are right Stackables!