I work with 2 bodies at a wedding with a 24-70mm f2.8L II on one and a 70-200mm f2.8L IS on the other. I don't change lenses on the bodies during the day. That occasion the shorter zoom was affixed to the 6D.

I used Adobe Bridge to download copies of the images to my HD. I am a Windows 10 user and have Adobe Photoshop CC 2019 on my machine. My worklow after a wedding allows me to backtrack from a 'final version' image to the original RAW file.

When this problem arose I went back to the 'Original RAW Files' folder and then to the SD cards (the original 'Originals') and put the cards through (i) the camera again (ii) Transcend's own recovery software RecoverRX (iii) Card Recovery (iv) EaseUS Recovery Wizard (v) Hetman Photo Recovery and (vi) Recuva all without success.

I haven't tried Canon's own software to download the original files but might just try that as well. I'm currently stuck indoors here as a result of the CoVid-19 lockdown so I've got nothing (more) to lose. Will update you later.

Hi Paul - thanks for the tip - this is my first thread and appreciate the advice.

The image file numbers I refer to are those created in camera. I only created different prefixes for different cameras so that I can tell which camera each image came from. I use Adobe Bridge to download copies of the images from the card to my HD. I use a seperate card reader to do so rather than the one built in to the PC. I am a Windows user.

rcarol - have already tried tha without success.

Several of you have suggested the problem may lie with having set the camera to shoot without a card in place, but there always was a card in the slot and latterly not removed when shots were taken before during and after the material time.

My thanks to all on this forum who have volunteered advice.

The range of suggestions have all been thoughts I have already had so I feel vindicated that my thought processes about resolving this have not been so far removed from so many other experienced photographers.

I will seek to have the camera checked by Canon and update the thread in due course.

Thanks EL Shapiro for your contribution. The card that was in the camera pre- group had captured some shots, the group shots (chimped and checked and apparently in order) and then some later shots. I did not switch the camera off as far as I can recall and I did not change the card. It was only later at home when the images were downloaded that there were no group shots to be found. As I have indicated earlier I am totally at a loss to explain what has happened. Also because of the current lockdown I don't have any recourse to having the camera checked over. I have taken a few more images with the camera and a different card but the 'issue' doesn't seem to have reappeared. Perhaps a look over by Canon technicians might be the answer. I will come back with an update as and when I can.

I can't imagine that I have deleted them as there are no file numbers missing (I checked and the numebrs are still in sequential order including the images taken after the group shots). I have used Transcend exclusively for several years starting with CF cards, following a bad experience with a Lexar card, before moving on to SD cards with the advent of SD slots as they became 'standard' in the 5D series along with CF card slots. I have on occasion used the CF card slot to create a 'back up' to the SD cards but I don't have that facility with the 6D body.

I use different prefixes with different bodies in order that there is no chance of an 'overlap' with similar numbered files. The occasion hasn't arisen but the prefixes would ensure that there would be no confusion. I merge all my downloaded files in Bridge sorting by time/date created and I have checked only the files from the 6D and can see no 'break' or loss of files in sequence. It's stumping me BIG time as to where these files have gone so the only answer I have come up with is that it was a faulty card. Worse case scenario is that there is an issue with the 6D but that's not something I can check during the current lockdown, hence my approach to this forum.

Thank you for your response. Yes the issue relates only to the 6D. I mentioned the 5D4 only to show that I use more than one body at a wedding and don't try to catch everything on 1 camera or 1 card. There is no great break in the timeline other than would be moving between shots or cameras. The card wasn't removed from the 6D during the relevant time period.

Sorry missed out the important part that the images were shot on the 6D which of course only has 1 card slot so I wouldn't have been able to save a back up on a seperate card.

I will pre-empt this post with a brief summary - I am a professional wedding photographer of 20+ years experience (both film and digital) and always with Canon equipment. I am meticulous in my prep for and execution of a wedding shoot. I have now come across an issue that quite frankly has me stumped.

I recently (pre CoVid-19 lockdown) shot a wedding with 2 bodies as I always do (5D4 and 6D) and used Transcend SD cards which I rotate regularly and always format to the camera before each shoot. The cards are less than a year old and probably only covered half a dozen or so weddings (I don't clear my cards until my Clients receive their Album.)

I downloaded the cards after the wedding and subsequently when going through them to prepare proofs for viewing I discovered I was missing group shots I'd taken mid way through the shoot. I have the shots from before that point in the day and I have shots from after but not the group shots.

The confusing thing is that (i) I recall checking the back of the camera that the shots were okay, and (ii) there are no missing file numbers when I check through the files I have. My cameras are set (with differing prefixes) to record images in consecutive order.

My initial thought was that the missing files ight still be somewhere on the card but having run the card through 5 seperate and different recovery programs there are nowhere to be found.

I can only surmise that I have a faulty card . . . or do I?

Thoughtful and appropriate responses sought. Thank you in advance.

doublebogey7 - just a thought that if you still have your old scanner, you might still be able to use it through using 3rd party software such as VueScan or SilverFast. Both are available to purchase and download online.

You've had many full responses to your questions but I don't see any response re speed writing to cards (unless I messed that when 'skimming'). Basically my understanding is that BOTH cards irrespective of individual writing speed, will write at the speed of the slowest card used. Enjoy your 5D3.

Thoroughly recommend Billingham bags. I have had my 445 for 20 years and still going strong . . . albeit a bit worn at the corners. Must be the best photographic purchase I've ever made . . . for longevity! LOL

Hi AJR - I can recommend CAMERA REPAIR DIRECT (www.camerarepairdirect.co.uk) in Cranleigh, Surrey. Very competent, very competitively priced and very reliable. You can contact them first to discuss your problem and then download an order form from their website to include when you send your camera/lens in. They will assess your camera/lens and contact you with an estimate for you to agree and instruct repair or have your your item returned. I have used them for both camera and lens repairs with equally satisfactory results.