Photostitch Panorama

Unlike some competitors in the mirrorless large-sensor bracket of the market the Canon G1 X does not come with a fully automated panorama feature. Both the Samsung NX200 and the Sony NEX series offer panorama modes that let you sweep the camera sideways across a scene and generate a fully stitched panorama as the end result. These panoramas are taken at a lower vertical resolution than single frame images but the quality is good enough (especially on the Sonys) for web-use. Most of all these systems are quick and convenient, eliminating the need for stitchgin in post-production.

The G1 X however comes with the same Stitch-Assist scene mode that we've seen on many generations of Canon compact cameras. The mode allows you to line-up the single frames you take to create a panorama but the actual stitching has to be done on your computer, using the provided Photostitch software. Unfortunately the quality of the end result is far from perfect. In the sample below you can see that out of 4 images taken with the G1 X's Stitch Assist mode Photostitch created a panorama with a bent horizon, visible 'seams' and some stitching errors. For comparison we used the same images to create a panorama in Adobe Photoshop CS5's Photomerge feature and the result is visibly better.

In the 'About' section of Photostitch you can see that software has been around since 1996 and judging by the distinct 'Windows 3.1 look-and-feel' of the interface hasn't changed too much since then (although the most recent update dates from 2008). The software clearly needs a refresh but, ideally we'd like to see a panorama function in-camera.

The Photostitch interface is very simple. You open your images and a press of the button starts the merging process. There are very few parameters available to play with.
Panorama created with Canon Photostitch 3.1
Panorama created with Adobe Photoshop CS5's Photomerge feature

HDR, iContrast and Shadow Correct

The G1 X comes with three different features to help enhance the dynamic range of a scene - iContrast, Shadow Correct and the HDR scene mode. The former two are accessed via the Func-menu, the latter is located within the image effects, which you can get to via the mode dial.

We've seen the iContrast featyre on other Canon compact cameras before and works in similar way to the Highlight Tone Priority (HTP) mode on Canon DSLRs. More highlight detail in the images is achieved by amplifying the sensor's output by one stop (200% DR) or two stops (400% DR ) less than usual, meaning highlight detail is less likely to be discarded. As a result iContrast ISO 200 (400) is, at the raw level, the same as conventional ISO 100 underexposed by one (two) stop(s). A modified tone curve then ensures you still get the correct image brightness, and any properly compatible raw converter should reflect this and be able to render the additional highlight detail.

The downside of this is that using a lower chunk of the sensor's response leaves more space to capture highlight information, but means shadow detail is recorded using the noisier bottom end of that output. Thus, when these tones are pulled up to the correct brightness, they tend to bring a bit more noise with them. This is visible in the shadow on the red boat and on the green boat to the left in the series of sample images below.


iContrast 200%

iContrast 400%

400% + Shadow Correct

Shadow Correct


Shadow Correct works much like the Auto Lighting Optimizer on Canon DSLRs. It is supposed to detect dark areas in an image and slightly lift them in order to increase shadow detail. There is an 'Off' and an 'Auto' setting for the feature and it cannot be used when shooting raw. The effect is clearly visible in the shadow areas of the frame which are brighter but again you pay for this with slightly increased shadow noise.

In HDR mode the camera takes three shots in quick succession at different shutter speeds and then combines the single frames to an HDR image. Canon recommends the use of a tripod to avoid camera shake but even when using a tripod you'll get some ghosting effects if you have moving subjects in your image. Overall the effect is fairly subtle with only small gains in highlight and shadow range but the end result can, depending on the scene, be quite attractive and vibrant.

Electronic 'first curtain' shutter

It's clear that Canon has implemented much the same electronic 'first curtain shutter' in the G1 X as is used by its EOS SLRs in Live View mode (although the G1 X uses an in-lens, rather than focal plane shutter). In other words, when you press the shutter button the exposure is started electronically, as opposed to closing the shutter, resetting the sensor then opening the shutter again. The physical shutter is only used to end the exposure.

This means that shutter lag (once the camera has been focused) is minimal, and makes the G1 X exceptionally quiet in operation (as long as you turn off all of the synthesised operational noises). Indeed it's almost too quiet - there's almost no feedback when you take a shot.