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SIGMA SD1 shots
- Thread starter darr
- Start date
darr
Well-known member
Old Gulf Station
Sigma SD1M + 12-24mm F4.5-5.6 DG HSM II (16mm) + 1/40 @ f/11, ISO 100
Here I am testing a used 12-24mm F4.5-5.6 DG HSM II after a copy of a 10-20mm F4-5.6 EX DC HSM fell short due to left side distortion. The 12-24mm performed well as long as I stay in the f/8 to f/16 range and be mindful of flare. I used artistic license to try and give an aged, but colorful presentation of the gas station. This lens is stellar sharp and I purposely added softness in post.
SD1m | 17-50/f2.8
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Spring Leaves
Sigma SD1M + 70mm F/2.8 EX DG Macro + 1/160 @ f/2.8 @ 400 ISO
Very nice photo, can you share how to process to have a great background like that. Thanks
darr
Well-known member
OlderThenDirt
Member
Hi Darr,
Did you add a soft glow to this shot of the Cabin "Somewhere In Georgia" or is that out of the camera. It's pretty.
Robert
Did you add a soft glow to this shot of the Cabin "Somewhere In Georgia" or is that out of the camera. It's pretty.
Robert
Somewhere in Georgia
Sigma SD1M + 35mm F1.4 DG HSM Art + 1/200 @ f/8, ISO 100
darr
Well-known member
Hi Robert,
I think I may have added a sunlight filter (NIK software) via post, but it was that magical time of day about an hour or so before sunset. It was already "pretty light," but as I stood on the other side of the fence and close to the road, I watched the sun-glow arrive, and then leave about 10 minutes after shooting. It was a beautiful experience, the type that drives me to get out in the landscape just to see if it will happen again.
Kind regards,
Darr
Great darr for sharing the IR shooting. Is it possible to have color IR photo?
The technical answer to your question for Darlene is "No".
IR (infra-red) is beyond human vision - it can not be seen. If it can not be seen, it can not have any color. So the only true IR image is black&white (greyscale).
But many IR shooters will apply false color to their images (there are many methods) to make them more interesting.
Ted
darr
Well-known member
Thank you Tam (and Ted).
IR photography with the SD1M is black and white. The false-color Ted refers to cannot be obtained with the SD1M unless the user can manipulate it in via post-processing somehow. The false-color IR photography seen on the web was produced by cameras that probably were modified at the sensor level, which the Foveon cannot be (I inquired at LifePixel). If I wanted to go that route, I would send my Sony NEX-7 to http://www.lifepixel.com/ , but IR photography for me is all about black and white.
BTW, your motorcycle photo is very stunning!
Kind regards,
Darr
Thanks Ted and Darr for valued explanation. I am wondering if we use IR590 instead of IR720, SD1m will produce some yellow/blue color as bayer sensor?
One more shot for Darr
One more shot for Darr
Darr, please allow me to clarify some statements.
Even with an IR filter attached to the lens, all 3 layers respond, including the "blue" top layer. And the X3F file itself remains a 3-channel color image.
Here is a raw histogram from a full-spectrum SD1M, shot with a Marumi 700nm on the lens.
If the shot is opened with anything that converts the raw data to RGB, you get a horrible red image which is why many people immediately select monochrome mode. For example, in SPP, my shot opens like this:
However, other converters are less severe, for example FastStone Viewer which puts up incorrect colors for normal Merrill images but does quite well with full-spectrum or IR-filtered shots:
Some applications can create raw composite images; they take the raw data as-is, scale it to an 8-bit TIFF and apply gamma correction:
Now the slight imbalance in the raw data is seen as a slight tint which could be further manipulated in post.
Knowing that Darr prefers monochrome, that application can also export any one of the three Foveon layer channels. Here is the red channel followed by the blue channel:
Both of those are as exported with no further processing. The red appears "better" to the eye but some say that the blue (top layer) gives sharper images.
All of the false-color images above came from a standard SD1M (dust-cover removed) with an IR filter on the lens. No post-processing at all except that I sharpened one of them. I've also had some fun by starting with a monochrome image then playing with individual RGB curves so that tint hues become dependent on pixel luminosity.
As to the term "false color" itself, I suppose any color other than grayscale in an IR image is "false" but I notice that satellite IR views of the earth are often quite deliberately colored presumably for analytical purposes.
Darr, Is that the kind of modification where the Bayer-pattern CFA is permanently replaced by a single color filter?
Ted
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Tam, the lowest I have is 680nm. Your 590nm will allow visible wavelengths to reach the sensor - more so than your 720nm. To guess what would happen you need to see the manufacturer's data for the filter - specifically the spectral transmission curve.
My guess is the image converted to RGB would still be dominantly red but with perhaps some yellow beginning to show if there is yellow-green in the scene. Just a guess. But you should be able to see through the view-finder to compose and the AF should be more reliable.
Ted
darr
Well-known member
darr
Well-known member
Tam,
Experiment and show us what you get, because I really do not know. I only use the Hoya IR720 because my objective is black & white, but I would be interested in seeing what you can produce with an IR590 filter.
Kind regards,
Darr