At the Edge of the City │ GH2 + Leica 45mm F2.8 │ 45mm F5.6 2.5s ISO160Whenever I get a new camera, I compare the image quality with my previous camera. This lets me know how much farther (if at all) I can push the new camera in marginal conditions: any gain in image quality will allow me to shoot in lower light and/or with a faster shutter speed.
So I check to see how image quality holds up as the sensitivity increases, using images from my old camera as a reference point. For the results to be relevant, I do the test at night under artificial light; in other words the kind of conditions that would warrant the switch to higher sensitivities. I choose an outdoor scene with enough fine structures in order to be able to judge at what point image noise starts to overwhelm detail.
Test Methodology
First of all, I compare image quality between cameras at the same aperture, shutter speed and approximate image brightness. That's to compensate for cameras where the sensitivity is either higher or lower than stated. As such different cameras may need different ISO values to achieve an image with the same brightness when both are set to the same aperture and shutter speed. This is the most relevant way I can think of comparing image quality. After all, I choose a specific sensitivity in order to achieve the desired shutter speed and aperture. And not the other way around.
For the test, the cameras where shot from a tripod using the self timer to release the shutter. I shot both the GH2 and the GF1 with the Leica Macro 45mm F2.8 lens with image stabilization switched off. Images were taken as close as possible to the same time and of the same scene so that lighting conditions are as similar as possible.
I then imported the RAW files into Lightroom tweaked the white balance and developed them using moderate sharpening and chroma noise reduction but no luminance noise reduction. For ease of comparison, I processed both cameras' files to 4000 x 3000 pixels. Obviously this isn't the only approach and other strategies will lead to different results. That's why I've provided links to the corresponding RAW files so you can experiment yourself.
Observations
The GH2 seems to be less sensitive than the GF1 at each ISO setting. Setting both cameras to F5.6 and the same shutter speed, the GH2's metering most of the time selected a 1/3 stop higher ISO – sometimes 2/3 stop. The resulting images were of approximately equivalent brightness, despite the different ISOs. So I would say that ISO1600 on the GF1 is equivalent to ISO2000 or 2500 on the GH2. Taking the discrepancies in sensitivity into account the GH2 image quality still seems almost a stop better than that of the GF1: judging from the 100% crops below, GF1 ISO1600 (approximately ISO2500 on the GH2) is similar to the GH2's output at ISO5000. Not bad at all.
Links to corresponding RAW can be found at the bottom of this entry.
RAW files:
GF1, F5.6, 3.2s, ISO 100
GF1, F5.6, 1/5s, ISO 1600
GF1, F5.6, 1/10s, ISO 3200
GH2, F5.6, 2.5s, ISO 160
GH2, F5.6, 1/5s, ISO 1600
GH2, F5.6, 1/5s, ISO 2500
GH2, F5.6, 1/10s, ISO 5000
GH2, F5.6, 1/20s, ISO 10000
Wednesday, February 2, 2011 at 18:00 ;)
XXX │ GF1 + Lumix 7-14mm F4.0 │ 7mm F4.5 1/800s ISO100Another extremely dull day, so I'll post a photo in my architecture series. This is the Ernst & Young Tower in Amsterdam's new Zuidas office district. Designed by Lord Norman Foster, I know the building intimately as Lindsey works there. The extreme wide angle and the converging verticals work well here in accentuating both the diagonal structure and the height of the tower. When using super wide lenses, I need to be very careful that distortion doesn't overpower the subject. So, for most wide angle shots, I tend to hold the camera level to keep verticals vertical – like in this photograph (click red link to open).;)
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