Dynamic Range

In a recent forum discussion on the Panasonic GH2 samples, which look really good, someone rightly pointed out the concerns about dynamic range. This has always been a problem with m4/3 in particular and digital sensors in general. 

From time to time we do some property photography, for estate agent websites and brochures. Interiors are very hard and test a cameras dynamic range to the limit. 

Below are two examples from a bracketed sequence, taken with a Panasonic GH1 and a 7-14mm wide angle zoom.

Panasonic GH1 7-14mm Zoom

The bottom shot is getting close to what is required for the interior, but the window is completely blown out and unrecoverable. So to get a satisfactory result we had to use the top version and lighten the dark areas both in camera raw and photoshop. We prefer this to using HDR as, for obvious reasons, a natural look is required. By working with the file we eventually came up with this.

Panasonic GH1 7-14mm Zoom

The "look" is right. Nice light bright interior and some detail in the window. Some of the exterior is burnt out but it works quite nicely. However there is a large amount of noise generated by the lightening and for the final clients version we would do more work, getting rid of that. Probably by replacing areas within the room with sections cut and pasted from other lighter shots. The section on the left with the shelf is particularly nasty and would have to be substituted.

With a suitable budget and the time to do it, a better result could be obtained by using some flash heads, but the circumstances dictated that this had to be done quite quickly and cheaply!!

So some problems with m4/3, but shots like this are very difficult with any camera. They were difficult with film and they are difficult with larger sensors also.

Heres another from the same shoot. This is the camera jpg taken with a Canon 5D MK II and 20mm lens.

Canon 5D Mk II 20mm f2.8 lens

The range is slightly less than the first shot, as there is more light and less dark areas.

The final result after Photoshop work looked like this.

Canon 5D Mk II 20mm f2.8 lens

Again an OK result with a light interior and detail outdoors. However there is still a burnt out sky, and a considerable amount of noise which would have to be eliminated.

Interior shots like this are incredibly difficult. You only have to look at the problems movie makers have with situations like this. Unless they use banks of interior lights, they will suffer from the same problems as above. In many cases, it just has to be accepted. Currently we have no film nor camera sensor that comes close to what our eyes can cope with. Someone in a recent forum expressed the concern that manufacturers obsession with higher resolutions has led to the problems of dynamic range being largely ignored. He rightly made the point that by now we should have something better than we have. Even the very best film or sensor camera/lens combinations are a long way off recording what we see with our eyes. We can come up with solutions because we have to, but it would make things a lot easier if we didn't. I'm afraid in-camera or software HDR isn't the answer. Can be useful for static subjects, though we are not convinced by what we have seen, but completely useless when one shot is all you get. 

In terms of m4/3, yes dynamic range is more of a problem than with larger sensors, though we've not seen any great improvement from the APS-C sensors we've used, and in the really difficult situations other solutions have to be found. They have to found for full-frame sensors as well as m4/3, so the notion that somehow these larger sensors solve all your DR problems is somewhat inaccurate. They don't. They may be marginally better, but it is marginal and we need somebody to come up with a satisfactory solution. However it still seems a low priority for camera manufacturers.

Finally, going back to the GH2 samples, they did seem to be no worse in terms of DR than the GH1. The high ISO performance looked excellent, with samples at ISO 3200 and 6400 looking very similar to the Canon 550D, which is high praise indeed. The upsizing of the sensor seems to have worked very well, as would have been expected. Panasonic wouldn't have done it if they knew it was going to be inferior to what they have already. If the samples translate to real world performance then they really have come up with something special, and deserve to be regarded as at the forefront of current sensor technology. A little more concern about DR wouldn't go unappreciated however.

D & A