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Why is C23 so slow generating previews and metadat?



  • LVS

    C1 recommends setting the Preview size to the same resolution as the monitor and indicates that setting it larger or smaller can affect performance. 

    Secondly, I think C1 does the Preview as a background task, so the user can work without delay. This of course is a problem if the user wants to sort through their images before editing. 

    I think an option in C1 Settings to allow the user to select background or immediate preview processing would help the situation.

    Were you running C1 v22 under Rosetta ? If you right/click on the application icon there is an option to run C1 v23 under Rosetta, I'm wondering if this may run faster especially if it doers not try to run previews in the background. 

  • Jerry C

    Capture One have been suggesting matching preview resolution to that of the screen. For a 5k monitor this produces previews that take up a lot of media real estate, about 10% of the size of the originals, and the biggest part of the catalog database file. Consequently catalogs with bigger Previews take longer to back up, as well.

    I did an experiment with version 21: No matter how I set Preview size, Capture One has to fit it to the viewer window and I actually saw only small differences in display speed no matter how I selected Preview size, or set hardware acceleration. Unless version 23 is different, Preview size continues to be more related to bulking up the catalog than improving speed of displaying an image.

  • PA

    Something definitely changed from 22-23 on the M1 Max in speed of preview generation.  I edit mainly on laptop and have previews set to recommended 3840.  The preview generation is so slow that even after a good minute or two after importing the first 20-30 images are blurry for 1-3 seconds before snapping into focus.  

    Could it be a Ventura compatability issue?  Photo Mechanic 6 was super slow to cycle between images since Ventura was released and the bug was JUST fixed recently.  Now I can cycle between images at supersonic speed.

  • Jerry C

    Going from one image to the next, Previews show up on the Viewer with some delay on my Intel iMac Pro and my Intel MacBook Pro. It could be worse with Apple silicon and Capture One 23, but I have no way of testing this. This has been going on for several iterations of MacOS and Capture One and the delay increases as my images files increase in size as expected. The delay is as you observe, but it is not significantly improved by matching the Preview size to the display resolution or changing hardware acceleration settings. Capture One loads the next image in the background while you are viewing an image, so if you go slowly from image to image, pausing briefly between images, you will not notice the delay. 

    I think the problem is more with Capture One and how it uses hardware acceleration, though this is not unique to Capture One. Cannon DPP 4 shows the same delay when displaying TIFF files, but is snappier with .CR3 files with no changes. The same is true with Photos.

    Capture One displays previews with many edits slower than a file with no edits. Capture One does not save the preview files with edits when you edit an image. You can see this when you open a catalog package and look at the preview files when you edit the image. So Capture One has to recalculate the edits. More edits, more delays. More so with layers. 

    I believe this is something that would require a lot of reengineering to improve as long as the edits must be recalculated. Even if there are no edits, Capture One is going to check to see if there are and this will slow things down a bit.

    This is just my theorizing. Someone who understands the engineering of Capture One might have a more cogent explanation.

  • Barbara Cook

    I'm working on high spec. MacBook Pro M2. It takes hours to take images to catalog. C1 v23. with Ventura for this point of view is rubbish. There are many bugs in library section. Sometimes after creating an album and then moving files from one folder to another within C1 you can't see moved images in folder structure. You can see them in album. I raised a support ticket - no answer. 

  • John Romer

    Adding my complaints on the issue. I just upgraded to the latest version ( and then uploaded 567 images from my Canon R7. Granted these are far larger images than I used to import given the newer sensor, and I am using Canon Raw CR3 files, so image size is about 24 mb a picture. Prior to the Canon R7 I did not use the CR3 format. Perhaps this image format is causing the slower load times and preview generation. For this latest batch the import took about 13.5 minutes and the preview generation took around 24-28 minutes.

    I am using a Mac Book Pro M1 Max with 64GB memory so I have maxed out the hardware I can throw at the application.

    For me, and others, Capture One faces an issue where it just seems sluggish and slow compared to prior versions. I feel slower processing images but I may not actually be slower. But impressions are what guides our emotional attachment to a system.

    They need to fix the issues that are causing consternation for others and look at benchmarking to ensure key steps of our workflow don't seem slow. Subscription issues aside, don't chase us away.

  • David Mantripp

    I've been doing a major cleanup of my metadata:  I'm now using PhotoSupreme as my golden source, and syncing data via XMP back to CaptureOne.  I have about 105'000 photos catalogued in PhotoSupreme.

    Today I exported metadata for all out-of-sync files (approx 65'000) from PhotoSupreme to file system.  It took about 3 hours.  I then started reading metadata back into CaptureOne.  Well, it's best estimate for the 95'161 variants I have in the catalog was something like 238 hours.  Hours. Not minutes.

    So I decided to divide by years,  For 2022 I only have about 2'500 photos. It was a quiet year.  Well, 20 mins ago C1 told me it would take another 5 minutes to load metadata.  It manages to process about 1 XMP file every 45 secs or so. I started the operation on these 2'500 photos about 6 hours ago.

    I see little point in ranting here, and there is a whole lot I like about C1, but this is absolutely pathetic. There's no other word for it.  It is very likely down to extremely bad database design.  It really seems that C1 does not employ a single competent database designer. I mean it isn't even a very complicated requirement - PhotoSupreme has a much more elaborate data structure, and as far as I know is a 1 man band.  I repeat, the only word to describe C1 catalog performance is "pathetic".

    Just as a comparison, LrC, which I keep around "just in case", sync'd the same 2'500 photos in under 10 mins.

    My system is fairly old - trashcan MacPro, 4 core CPU, 64Gb RAM, C1 catalog on internal SSD,  but that doesn't seem to be the issue as neither CPU nor RAM are anyway near flooded.   I have been considering upgrading to a Mac Mini M2Pro, or Studio M1Max, but it seems at least for C1 purposes it would be a waste of money.

    "about 2 mins left". Yeah, right. 


    oh, and P.S., when I ask C1 to "Load Metadata From Files", why the (redacted) does it decide to randomly build a bunch of previews as well? Was just tackling reading a bunch of 10kb text files not challenging enough?

  • David Mantripp

    So anyway I decided to leave it running overnight to do the next 2 years.

    10 hours later:

    Come on CaptureOne....  you can do better than this.

  • Fanjan Combrink

    Thought it was just me but updated to 23 a week ago and OH MY WORD!!!! It is SOOOO SLOW!! I had to import over 13000 images which took a whole day to do for some reason. Then I waited for the preview generation and that took another whole day, only to not make a difference in my culling speed cause I still have to wait for previews to load whilst culling between images. C1 seems to regenerate the preview between images whilst I cull slowing down things considerably.

    Even applying a Curve to all images takes soo much longer now, and this relates to a session with only 2000 images. Auto adjust all those images, also seems so much slower.

    It really got me annoyed cause for a piece of software that costs 4 times as much as the competition, it really makes you wonder why? 

    Want to see if I can go back to C1 22.

  • PA

    I paid big money for Capture One over the years including switching to subscription.  While C1 is expensive I am ok with it IF it saves me time.  This is instead COSTING me time.  The speed it takes to process previews on uncompressed Sony A1 files is like watching a dot-matrix printer attached to a machine with an 8086.  Apple pushed computing to the next generation with the M-series chips.  Capture One somehow figured out a way to reverse that.  I have to now select 10-15 images from a shoot because I do not want to wait the whole day for a shoot to process.  Something happened from 22 to 23.  22 was was faster at preview generation.

  • Fanjan Combrink

    PA It feels a bit like Capture One, with the introduction of the M1 said: Oh look at all this processing power, sooo much capacity, let's add all those features we wanted to add that people will love when they discover them.

    Now it just seems slow and makes me wonder about sticking with Capture One. I don't want to pay for Adobe cause I have the Affinity Suite for all my needs including my retouching needs. I also found the behaviour between Fujifilm and Capture One tethering to be hit and miss. It connects fine and I setup my shoot. Wait for the shoot a bit, then the tethering does not want to work once I want to start shooting. 


  • Tomek

    I just read all these posts and am now desperate - I have just have moved to subscription from a permanent licence and am already regretting it. I thought the slow preview render was because of my "only" 6-core AMD Ryzen 5, but if an M2 chip can't handle it, the problem is certainly elswhere. Capture ONE - keep your fans happy don't make us all go to competition!

  • Jerry C

    I don't see how the subscription version would work differently than the corresponding perpetual license version. I think you are referring to being able to use your perpetual license if Capture One designed some new feature that slows down the next version. I have a perpetual license for that reason.

    Using Capture One version on my M2 Ultra Mac Studio with 2TB storage and 128 RAM with Capture One catalog and 65k referenced files on an external OWC Envoy Pro FX Thunderbolt external NVME SSD and hardware acceleration set to Auto, it takes .39 sec per image to regenerate previews. So, it would take 7 hrs for all images. Display of All Images or a search of all images with a specific key word takes 2 sec. When editing, sliders have virtually no delay. Brushes have no delay. Moving rapidly between images takes a half second or less for 45k images. Pausing half a second between images to look at an image hides the delay because Capture One loads the next image in the background.

    I did notice that things slowed down after version 21. I also think the current code does not take full advantage of the M2 chip architecture, but it seems to have improved. With repetitive tasks, all of the cores show activity. Inefficiencies of the code are compensated by the speed of the M2. For the past 40+ years software inefficiency has depended on hardware gains to compensate. Some companies are better at recoding. For my use (no weddings, no studio, rare tethering), Capture One on an M2 Ultra Mac Studio is very fast.



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