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How to send RAW photo files fast

A single wedding can leave you with 1,500 frames and 40 GB of .ARW or .CR3 — and the client wants them tonight. This guide covers why RAW uploads crawl, what actually speeds them up, how long a shoot of your size really takes on your connection, and how to prove the files landed untouched.

Short answer

Send the RAW files as-is over a link-based transfer that uploads in parallel parts and can resume — not through email, not through a syncing cloud drive. Zipping them first does almost nothing (RAW is already compressed), and converting them to "save space" is the one step here that can actually cost image data. On Rabbitdrop, drag the whole shoot in and a lossless pass shrinks the files before they leave your machine — up to 25% on compressed RAW, and up to 50% if you shoot uncompressed RAW or work with uncompressed TIFF and DNG. How much you actually get depends on the format, and a few are already so tight that they are sent untouched. Whatever happens, the file your client opens is bit-for-bit the original.*

Why RAW uploads are so slow

It's rarely one big problem. It's five small ones stacked on top of each other:

Your upload speed isn't your download speed. Most home and hotel connections are asymmetric — a "500 Mbps" plan often uploads at 20–50 Mbps. The number that matters for sending a shoot is the upload figure, and it's usually the one nobody quotes you.
RAW files are big and there are hundreds of them. A 45 MP CR3 is 50–60 MB; a 61 MP ARW can pass 120 MB uncompressed. Multiply by a full shoot and you are moving tens of gigabytes.
Per-file overhead adds up. Services that handshake once per file spend real time on 800 files before a single byte of image data moves. Uploading files in parallel parts is what removes that tax.
Sync clients are competing with you. Lightroom cloud sync, a photo backup app, and a desktop drive client will all quietly use the same uplink you're trying to send on.
One dropout costs you everything. On a service without resumable uploads, a sleeping laptop at 90% means starting the whole shoot again — which is why a 40 GB delivery so often takes two nights instead of one.

Send a RAW shoot fast: step by step

  1. 1

    Copy the files off the card first

    Uploading straight from an SD card over a slow reader adds a bottleneck that has nothing to do with your internet. Ingest to a local SSD, then send from there.

  2. 2

    Cull before you send, not after

    The fastest gigabyte is the one you never upload. Dropping the obvious rejects usually removes 30–50% of a shoot, and it costs you five minutes instead of an hour of uplink.

  3. 3

    Get on the fastest link you have

    If Wi-Fi is what's holding you back, run a cable from the computer to the router; the studio also beats the venue. If you're stuck on hotel Wi-Fi, start the transfer anyway — with resumable uploads you can continue it at the office instead of restarting.

  4. 4

    Quiet the other uploads

    Pause Lightroom sync, cloud backup, and any drive client for the duration. They share the same narrow uplink and will happily halve your transfer speed.

  5. 5

    Drop the whole shoot into Rabbitdrop at once

    Go to rabbitdrop.com, drag in every RAW file together. No account, no client software. They upload in parallel parts under one link, and a lossless pass shrinks eligible RAW files before they go out.

  6. 6

    Send the link and let it finish

    Copy the short link and send it. Your client downloads in the browser — no account and no app on their end. If your connection dies, the transfer picks itself back up; you don't need to babysit it.

Six things that actually make RAW transfers faster

Upload in parts, in parallel

A single-stream upload rarely saturates your uplink. Splitting each file into parts and sending several at once does — and it's what makes resuming possible.

Shrink in transit, not by converting

Our lossless pass re-packs the same image into fewer bytes and unpacks it on arrival — nothing is thrown away. Converting the files yourself is the risky version: a lossy DNG drops pixels for good, and even a lossless DNG hands your client a different file from the one your camera wrote.

Skip the ZIP

A ZIP barely dents compressed RAW — a couple of percent — and on uncompressed RAW, where it would actually save something, our own pass saves more. Either way zipping a 40 GB shoot costs 20 minutes or more of single-threaded CPU, a second copy on your disk, and an archive your client has to extract.*

Plug into the router if Wi-Fi is the limit

This is the cable between your computer and the router while the upload runs — not the one you use to pull files off the camera. It helps when Wi-Fi is the bottleneck: a weak signal, a crowded venue network, or an uplink faster than the link can carry. On healthy Wi-Fi with a slow uplink it changes nothing.

Pick a service that resumes

On a multi-hour upload, the question is not if something interrupts it but when. Resuming from the last completed part turns a disaster into a ten-second pause.

Don't make the client install anything

Half the "it's still not here" emails are the recipient fighting an account wall or a desktop sync client. A plain browser download link removes an entire category of delay that has nothing to do with bandwidth.

How long will your shoot actually take?

Roughly 500 compressed RAW frames at 25 MB each is about 12.5 GB. Here's what that costs on typical upload speeds — check yours with a speed test and read the upload number, not the download one.

Upload speed 12.5 GB shoot 40 GB shoot
5 Mbps~5 h 30 m~17 h 45 m
10 Mbps~2 h 45 m~8 h 50 m
25 Mbps~1 h 5 m~3 h 35 m
50 Mbps~35 m~1 h 45 m
100 Mbps~17 m~55 m
500 Mbps~3 m 30 s~11 m

Two things move these numbers in your favour: culling, and sending fewer bytes for the same pictures. Even a 15% saving on a 40 GB delivery is six gigabytes you never upload — on a 25 Mbps uplink that's over half an hour back.

Under the hood

Why RAW moves faster through Rabbitdrop

Most transfer services treat a 60 MB .ARW exactly like a 60 MB PDF. Rabbitdrop reads the file's actual structure and re-codes the parts that can be re-coded reversibly, in your browser, before anything is sent.

Fewer bytes on the wire

Up to 25% on compressed RAW in internal tests — Sony ARW and Canon CR2 sit at the top of that range, Nikon NEF lower down. Uncompressed sensor data gives up to 50%.*

Lossless or nothing

Every transform is verified during encoding: the file is decoded back and compared with the original. If it isn't bit-identical, the original bytes are sent untouched instead.

Honest about what it can't do

Some formats are already packed so tightly that there is nothing left to win — those are sent exactly as they are. What you gain depends on the format; everything else here — parallel parts, resume, a bit-for-bit delivery — is the same either way.

That second figure matters more than it looks. If your camera offers both "uncompressed" and "lossless compressed" RAW — most Nikon and Sony bodies do, as do medium-format backs — the uncompressed file starts far bigger but can give up to half of itself in transit, so the gap between the two settings narrows sharply on the wire. The same applies to uncompressed TIFF or DNG coming out of a scanner. (A compressed original is still the smaller file overall; this only closes the distance.)

The practical rule: the slower your uplink, the more the pass pays for itself. Compressing costs real CPU time, so on a fast connection the bytes it saves can be worth less than the seconds it spends saving them. With a whole shoot the two overlap and the trade tips back in your favour; with one small file on fibre it barely matters either way. See the RAW photo transfer page for the full format list.

How to prove the RAW files arrived intact

"Lossless" is a claim you can check yourself in about thirty seconds. Take a checksum of the file before you send it, take one after your client downloads it, and compare the two strings.

macOS / Linux

shasum -a 256 DSC01234.ARW

Windows (PowerShell)

Get-FileHash DSC01234.ARW -Algorithm SHA256

Identical hashes mean identical files — same pixels, same EXIF, same embedded preview, same everything. It's also the quickest way to catch a service that quietly "optimised" your photo on the way through.

Frequently asked questions

What is the fastest way to send RAW photos to a client? +

Cull first, then upload the remaining RAW files as-is through a link-based transfer that uploads in parallel parts and can resume after an interruption. Avoid email, avoid syncing cloud drives, and don't convert the files to a smaller format first — that's the one step that can actually cost your client image data.

Should I zip RAW files before sending them? +

Usually not, though the reason depends on what you shoot. Compressed RAW barely responds to a ZIP — single-digit percentages — because the camera already did the entropy coding. Uncompressed RAW does compress, but our lossless pass takes up to 50% off it, more than a ZIP would. And either way the ZIP costs you 20 minutes or more of single-threaded CPU on a 40 GB shoot, a second 40 GB copy on disk, and it hands your client an archive to extract instead of files they can open.

Why is my upload so much slower than my download? +

Most consumer connections are deliberately asymmetric — cable and DSL plans dedicate far more capacity to download than upload. A 500 Mbps plan can easily upload at 20 Mbps. Run a speed test and plan your delivery around the upload figure.

Can I send RAW photos without losing quality? +

Yes — as long as the service transfers bytes rather than processing images. Rabbitdrop's compression is fully reversible and verified during encoding, so the .ARW or .CR3 your client downloads is bit-for-bit the file you shot. You can confirm it with a SHA-256 checksum on both ends.

What happens if the upload is interrupted halfway through a shoot? +

You continue instead of starting over. Files upload in parts, so a dropped connection or a sleeping laptop resumes by itself, and you can pause and resume by hand. If the tab was closed, reopen Rabbitdrop within 24 hours and pick the same files — only the parts that never reached storage go up again. More on resumable uploads.

Is it faster to send RAW or converted DNG files? +

Converting to lossless DNG can reduce size, and the gain is biggest exactly where you'd expect it: uncompressed RAW. But the conversion takes time, and your client no longer receives the manufacturer's original file — which matters if they use camera-specific profiles or need to re-open it in the vendor's software years later. A lossless transfer pipeline gets you most of the same benefit for free — up to 50% off uncompressed RAW — while your client still receives the original file.

Send your next shoot in one drag

No account, no client software, no quality loss.

Start a RAW transfer →

Keep reading

Free large file transfer for photographers

What the free tiers really cover, and when a shoot outgrows them.

RAW photo transfer

Every supported RAW format, from .ARW and .CR3 to BRAW and R3D.

* Compression figures come from internal tests on synthetic and real files and depend heavily on camera, format and content. The ZIP timing is a measured deflate rate on incompressible data; a faster machine will beat it, an external drive will not. Some formats are passed through unchanged. Upload timings assume a steady connection and no competing traffic.