Canon and iPhone

RAW, JPEG or HEIF when the camera is tethered to a phone

October 17, 2026 · 3 min read

Tom laughing in a dark coat on a cobbled street in warm evening light — A Large JPEG, 6 MB, on the phone in about a second. The CR3 next to it stayed on the card for the edit.

The file setting you chose for your editing workflow is now also a decision about what the person in front of you gets to see. A phone on the camera can only show what it can decode, and a Canon RAW file is not on that list. Here is what to set so you lose nothing on either side.

The problem with RAW on a phone

Canon's RAW format, CR3, is not decoded by iOS. The file transfers fine over the cable; the phone just has no picture to draw from it. An app can save the CR3 and tell you it arrived, but the thumbnail stays blank, and the person you want to show it to sees a grey square. The same is true of a Sony ARW or a Nikon NEF on an iPhone without a third-party decoder.

The fix: a JPEG or HEIF next to the RAW

Every Canon EOS can write two files per shot: RAW to one slot or the same card, plus a JPEG or HEIF. Set it in the red menu, Image quality. Pick RAW (or C-RAW) in the first column and a JPEG or HEIF size in the second. Now each press of the shutter gives you the RAW for the edit and a finished picture the phone can show and send.

Setting	Phone sees	Edit gets	Per shot over the cable
RAW only	Nothing to display	RAW	25 to 45 MB (if kept)
RAW + Large JPEG	Large JPEG	RAW	About 6 to 10 MB
RAW + Medium JPEG	Medium JPEG	RAW	About 3 to 5 MB
RAW + HEIF	HEIF	RAW	About half of the JPEG
JPEG or HEIF only	The same file	The same file	As above

With StreetKit the phone displays the JPEG or HEIF and leaves the RAW on the card unless you turn on Keep RAW, which stores the CR3 alongside without a preview.

JPEG or HEIF

HEIF is Canon's 10-bit option, turned on with HDR PQ shooting on bodies that support it (R3, R5, R6 Mark II and later). The files are about half the size of a JPEG at the same quality and the iPhone displays them natively; the Photos app has used HEIF for its own pictures since 2017. Two cautions: a Windows desktop may need a codec to open them, and some web services still convert them on upload. For a phone-first workflow HEIF is the better file; for sending to someone with an old PC, JPEG is safer.

What size

Large. The cable moves a Large JPEG in a second or two, so the saving from Medium is not worth the pixels. Where it matters is the upload from the phone: the preview that reaches the person scanning the code is made on the phone and is small regardless, and the full file goes up over Wi-Fi by default, so a Large JPEG costs nothing on the street and gives them the real thing later.

Picture style suddenly matters a little

With a RAW workflow you never think about Picture style, because RAW ignores it. The JPEG does not. It is the file the person gets on the spot, so pick a style you would be happy to hand over unedited: Standard or Neutral, sharpness a notch down, and leave it. Nobody has asked for the edit because the proof was too neutral.

Shooting RAW only on purpose

If you must, because of card space or habit, know what you give up: nothing on the phone to show, nothing to send, and a share page of blank tiles. For street portraits where the point is the hand-over, that is the wrong trade. Switch to RAW + JPEG for the walk and back to RAW only for the studio.

Questions people ask

Does RAW + JPEG slow the camera down?

Not noticeably on a modern body. The buffer fills a little sooner in a long burst. For portraits at three per press it makes no difference.

Can the person I photographed get the RAW?

If Keep RAW is on and the originals have uploaded, the RAW can be downloaded from their page, shown as its preview JPEG. Most people do not want it, and the JPEG is what they can actually open.

What about C-RAW?

Canon's compressed RAW is fine for the edit and saves card space. It is still not displayable on the phone, so the JPEG next to it matters just as much.