Sigma test SD14, SDQ sensitivity and range

[dabateman]

I have started to test out the Sigma SDQ. Its an interesting camera. The viewfinder with live view makes it easier to focus on still objects. However the range is similar to that of the SD14. Both the SD14 and SDQ are black with a 313 filter. The Olympus EM1 can pull off a 300bp10 filter. The Sigma cameras seem to be UV-A cameras only. However it does offer better noise on the higher shutter speeds than the SD14, but not the EM1.

 

Lens Pentax 85mm f4.5, set at f8. One 125W mercury light was used as source, the lucky herb self ballasted light.

For all images below the SDQ was set to Monochrome with Blue selected, high resolution mode. The Olympus EM1 was also set to Monochrome in camera. The SD14 files were converted to monochrom with Sigma Pro, no other adjustments.

 

SDQ filter 335bp10 with BaaderU to cut out IR leakage ISO 100 f8 120 seconds:

 

SD14 filter 335bp10 with BaaderU to cut out IR leakage ISO 100 f8 120 seconds:

 

Olympus EM1 filter 335bp10 with BaaderU to cut out IR leakage ISO 200 f8 120 seconds:

 

What's interesting is that the dynamic range of the SDQ seems lower than that of the SD14.

 

SDQ filter BaaderU ISO 100 f8 2 seconds:

 

 

SD14 filter BaaderU ISO 100 f8 2 seconds:

 

 

Olympus EM1 filter BaaderU ISO 200 f8 2 seconds:

 

The SDQ seems to blow out the highlights more, having less dynamic range than the SD14. I shoot High resolution mode and Low resolution mode and see a little difference between the images. The low resolution mode (similar to the SD14 with 3 equal layers) holds onto micro-contrast better, but still has lower DR. The High resolution mode (4:1:1 mode) is flatter. However the SDQ has an interesting multishot mode called SFD, which merges 7 images together. This

 

SDQ filter 335bp10 with BaaderU to cut out IR leakage ISO 100 f8 30 seconds with 7 merged SFD mode:

[Andrea B.]

Interesting....

However, the Sigma camera tests are pretty much convincing me that they really aren't the best cameras to use for UV. And in comparison here, the Olympus EM1 is so much better.

 

Question: Is that the blue channel from the EM1 photo? Or is that a 3-channel monochrome?

 

The problem with the SFD merge, which seems to be an HDR type of effect, is that it seems to lighten the UV-dark areas too much. But it is interesting to see a result from this setting anyway.

 

((Not sure why you are putting a BaaderU over a 335bp10 to cut IR block. Wouldn't an S8612 be better?))

[dabateman]

Andrea,

For the Em1 I just set it to monochrome in camera and left the other settings at default. I know the blue dye is more sensitive with my 390nm filter and the grern dyes more so with my 370nm and 335nm filters. So I could play with that in the future. I just wanted in camera monochrome to try and level the playing field.

 

As for filters, I only have a 2mm S8612. My Baader venus filter is 72% transmission at 330nm. So it is actually better to grab the 334nm line from my mercury vapour lamp and avoid any IR. Both Sigmas were more sensitive to IR, than the Em1. I was not able to get a good UV image with my 340bp10 filter only. I can get a nice color image with the Olympus.

 

Since I own the SD14, I will not buy a SDQ. The SD14 is a bit more sensitive than the SDQ and has larger dynamic range. What interests me now with the SDQ, is its a very good monochrome camera. Very fun to play with. But I haven't fooled around enough with my Em1 in monochrome and might be similar.

 

If you didn't own any camera for UV work. The SDQ may be a good starter camera. It has an ok EVF, and magnified preview. You could customize in camera filters using the dust blocker with alternative filter glass. For UVA its nice in monochrome and handles the Baader filter very well with live preview. Also the HDR SDF feature is nice and can be edited in the Sigma software to be based on 3 to 7 images, which are photographed at different exposure settings. I would recommend using the low resolution more than the high resolution mode. It is similar to the SD14 for file size, look and pop. The high resolution mode is a little flat. Doesn't have the typical Sigma 3 channel look. However the dynamic range is less than the SD14. So I can see why they added the SDF hdr mode.

 

 

[Andrea B.]

As for filters, I only have a 2mm S8612. My Baader venus filter is 72% transmission at 330nm.

 

Ah yes...understood.

 

[[Added Later: Just had a little power flicker here in the middle of my next comment. Had to come back and re-write it.]]

 

Thanks for these comments about the SDQ. :)

[dabateman]

One thing I just noticed that the Baader venus filter images above show is the magnification differences. The SDQ has a 1.5x crop sensor in 3:2 format. The SD14 has a 1.7x crop sensor in 3:2 format and the Olympus Em1 has a 2x crop sensor in 4:3 format. All the above images were resized in Infran viewer to 800x600 as a standard setting. That can be an other reason why the Olympus images look better. Four thirds is a better format, but if you want wide the SDQ gives you a wider view. The SDQ-H would be even wider with its 1.3x crop sensor at exact same pixel density scaled as the SDQ. Its a 6Mpixel low resolution mode rather than the about 5Mpixels of the SDQ