Convert ORF to TIFF

Olympus and OM System bodies compensate for a smaller sensor with computation, and High Res Shot is the clearest example: the sensor is shifted by fractions of a pixel between a series of exposures and the results are combined into a single frame of far higher resolution, around 50 megapixels handheld and about 80 on a tripod on recent bodies. It is the reason a lot of Micro Four Thirds photographers own the system at all.

Whether that composite reaches you here depends on what the camera embedded, and the converter gives you a direct readout of it. Every JPEG inside the file is found and the largest by pixel count is the one kept, so the dimensions of the TIFF are exactly the dimensions of the biggest picture the camera wrote. Convert one frame and look: 8,160 by 6,120 means you have the composite, 5,184 by 3,888 means the camera embedded its ordinary preview and the extra resolution is still locked in the sensor data.

An ORF carries 12 bits per channel — two below the 14 that Canon, Nikon, Sony and Fujifilm write, a quarter of the tonal levels, which is a real difference on a smaller sensor where the shadows are the first thing to give way. It also carries the composite data from a High Res Shot, the white balance as a changeable parameter, and the full metadata block.

None of that is in the TIFF. The extraction takes a finished eight-bit picture the camera’s processor produced, which means the Picture Mode, the white balance and the noise reduction are decisions already made. On a Micro Four Thirds file, where noise reduction choices matter more than on a larger sensor, that is worth knowing: the camera’s smoothing is baked in and cannot be dialled back.

Divide the pixel dimensions by the pixels per inch you intend to print at. A standard 5,184 by 3,888 frame gives 17.3 by 13 inches at 300 ppi and 21.6 by 16.2 at 240. A 50-megapixel High Res frame at 8,160 by 6,120 gives 27.2 by 20.4 inches at 300 and 34 by 25.5 at 240. An 80-megapixel frame at 10,368 by 7,776 gives 34.6 by 25.9 and 43.2 by 32.4.

The number to use depends on viewing distance far more than on the printer. Three hundred is the figure for something held in the hand; a picture hung on a wall and looked at from two metres is perfectly served by 200, which turns the standard frame into a 26-inch print. Nothing here changes those numbers, because the conversion does not change the pixel count — it only decides what the pixels are stored in.

Four bytes a pixel and no compression at all. That makes the standard frame 80.6 MB, the 50-megapixel High Res frame about 200 MB, and the 80-megapixel one about 322 MB. The ORF they came from was probably between 17 and 40 MB.

Those are files that behave differently from what most people are used to. A 322 MB TIFF is slow to copy over a home network, will not go through most upload forms, and will make an older editor think about it for a while when opened. If it is going to a lab, ask about their ceiling first; if it is going into a layout, place it and let the layout program handle the resolution rather than shipping the full file around.

The 12 bits per channel in the ORF became eight when the camera wrote its preview, so the TIFF holds eight even though the format allows 16 and 32. For a picture that is going straight to print, eight bits is what a print reproduces anyway.

It becomes the binding constraint the moment the file is edited. A large smooth area — a clear sky above a landscape, a plain wall in an interior, the background of a copy shot — has a limited number of levels available in eight bits, and stretching the contrast across it produces visible steps. A 16-bit development from the ORF has sixteen times as many levels to distribute and absorbs the same edit invisibly. If the print is important and the picture has big smooth areas in it, that is the argument for OM Workspace rather than this page.

No compression, one strip, photometric RGB, eight bits per sample, four samples per pixel with the fourth declared as alpha, and no ICC profile. It is the most conservative TIFF the specification permits, chosen because the readers that ask for TIFF are the ones least likely to agree about anything more elaborate.

The missing colour profile is the part that matters for a print. Olympus bodies offer sRGB and Adobe RGB, and the preview inherits whichever was set; the TIFF carries no label, so a lab’s software will assume sRGB. If the camera was on Adobe RGB the saturated colours will print duller than intended, which is a common and easily missed failure. Check the menu, or develop the file in colour-managed software when the colour is the point.

High Res Shot is not the only mode where the OM system computes rather than merely records. Live Composite builds an exposure over time, Live ND simulates a filter, in-camera focus stacking combines a series, and HDR merges brackets. In each case the picture the camera shows you is the result of that computation.

This is the one place in the raw bundle where extracting the camera’s own rendering can be an advantage rather than a compromise: for a computed frame, the camera’s JPEG is the finished article, and a third-party raw developer may or may not reproduce the same computation from what is stored beside it. Before deleting anything, convert the frame here, open the ORF in whatever developer you use, and compare the two. Which one is better is a question about the mode, not a general rule.

Decoding and re-encoding drops the entire block. No lens or focal length, no aperture, shutter speed or ISO, no capture time, no GPS coordinate from the body or a paired phone.

For landscape and wildlife photographers that last one is a benefit worth naming. A location tag on a picture of a nest, a rare plant or a specific viewpoint travels further than people expect once a file is shared, and the TIFF does not have it. If you need the capture data, read it out of the ORF and keep it beside the print order rather than expecting the derivative to carry it.

Everything runs in the browser: the file is read locally, scanned for its embedded JPEGs, decoded and written back out as a TIFF. There is no software to install, no account and no upload, which makes this practical on a borrowed laptop, a work machine or a tablet in a hotel room after a day out.

The free tier accepts input files up to 100 MB. Every ORF clears that easily, including High Res Shot files, which are larger than ordinary frames but still well under. The size that will cause you trouble on this pair is the one coming out, not the one going in.

The TIFF is a delivery. The ORF is the only file that still holds the 12-bit sensor data, the High Res composite information and the option to make a different rendering later — a warmer white balance, less noise reduction, a shadow recovered.

Prints get reordered and reprinted, sometimes years later and often larger than the first time. Extract a TIFF each time you need one, keep the ORF files organised by trip, and develop properly the small number of frames that turn out to matter. Nothing in that pattern throws away something that cannot be recovered.