Lulworth castle Dorset

[derekphil]

[Manfred M]

Evaluating highly manipulated images like this one is always a bit challenging unless you provide some details as to what you are trying to accomplish.

My guess is that this is a day-to-night look you are after, but the lighting isn't quite working out. It looks more like a mid-day shot with some sky darkening. A bit of perspective correction on the castle itself would be useful (so it doesn't look like it is collapsing).

It would be interesting to see the original image to understand where you went with this image.

[rpcrowe]

I suspect that this is an IR image...

[Manfred M]

I suspect that this is an IR image...

Dark sky with IR suggests a red filter, but as this is a colour image, that wouldn't be the case. When I did colour IR work I never had a sky that looks like this and in colour I would expect a pink tinge to the leaves as they transmit IR wavelengths.

Again a bit of information as to what is going on here would be useful.

[Shadowman]

Nicely captured and processed.

[Wavelength]

From a non-analytical point of view, i liked what i see...But in a forum like this Manfred's approach is very important

[derekphil]

Confirming that this is an IR image, and so is (has to be) very heavily processed.
The colours are all false, and where you end up with the colours of grass, leaves, sky, etc, is largely up to the post processing, and personal preference.
IR is not universally liked, but I like it for its ability to turn an ordinary image into a dramatic, surreal one.
Many thanks for your comments.

[Manfred M]

Thanks for the information. Again, it would be interesting to see what the image looked like out of the camera to see what additional work has been done to it. The dark sky is of particular interest to me as that is not what I would normally associate with a colour IR shot.

[derekphil]

Manfred,
Here's the original, it's just reduced in size and jpegged.
I'm not sure what you will learn, a straight-out-of-the-camera IR image is a mess until you swap R and B channels.
From memory, I think I had a blue-ish sky, but there were other colour artefacts that proved dificult to control, and the result was the effect I liked best.
A lot of IR images have dark, going on black skies.

[Manfred M]

Manfred,
Here's the original, it's just reduced in size and jpegged.
I'm not sure what you will learn, a straight-out-of-the-camera IR image is a mess until you swap R and B channels.
From memory, I think I had a blue-ish sky, but there were other colour artefacts that proved dificult to control, and the result was the effect I liked best.
A lot of IR images have dark, going on black skies.

Thanks for posting this. This is much more along the lines that I would have expected. Colour IR film and B&W IR film that I used to shoot was a lot more predictable in outcomes. I would shoot Ektachrome IR without a filter and the main effect was that leaves and grass had a light pink colour. B&W IR film was often shot with a Wratten 25A (red) filter that would knock the cyan out of the sky and give those super dark skies.

Another problem I remember from the film days was metering was a real pain as the light meters would not take the IR component into consideration when calculating the exposure so shots often came out overexposed. Histograms on digital cameras make this whole exercise a lot easier. Your exposure looks quite good on the red channel; you've lost a bit of shadow detail, but the highlights are right where they should be. This suggests that the blue and green channels are "under-represented".

Thanks for this information - you've given me a lot to think about.

[derekphil]

I've never tried IR film, it sounds like a can of worms. Using digital and liveview gives control of exposure and focus, and takes a lot of the guesswork out.
I don't understand what you mean by blue and green being under represented. I've posted two variants, one with the tradtional B R swap, and one with the swap plus B and G increased by about 20% each. I could live with either, but processing more with channels and luminosity will improve the image.

[rpcrowe]

Manfred wrote that Ektachrome IR film give the foliage a pink color... There was a also Camouflage Detection Aerial Ektachrome film the would show the live foliage in a pretty vivid red while dead foliage and phony foliage used as camouflage would turn out black. This was quite useful in spotting camouflaged areas in reconnaissance photography, especially of jungle areas...

Here's a review of IR conversions of digital cameras...
https://www.youtube.com/watch?v=ZvVZLGg0LC8

[xpatUSA]

I've never tried IR film, it sounds like a can of worms. Using digital and liveview gives control of exposure and focus, and takes a lot of the guesswork out.
I don't understand what you mean by blue and green being under represented. I've posted two variants, one with the tradtional B R swap, and one with the swap plus B and G increased by about 20% each. I could live with either, but processing more with channels and luminosity will improve the image.

I do like the choice of subject for your IR shots. With my DSLR, such shots are easy - the UV/IR blocking filter pops out of my camera with my thumbnail, et viola, instant full-spectrum work! And, with the Foveon sensor, channel-swapping isn't de rigeur, quite nice shots are possible even without an IR filter popped on the lens.

About the only other big advantage the Sigma has over "most of us" ...

[derekphil]

That's interesting; I hadn't heard of a blocking filter that's so easily removeable (and replaceable!). Which Sigma is this?
Being able to use a variety of IR filters would be an advantage, as would taking visible spectrum images on the same camera.
I know little (nothing) about the Foveon sensor, are you saying that blue and red channels do not need to be swapped to get an acceptable image from IR?
Can you post some images of full spectrum and IR images from this camera, please?

[xpatUSA]

That's interesting; I hadn't heard of a blocking filter that's so easily removeable (and replaceable!). Which Sigma is this?

All the Sigma DSLRs have that feature, plus their two recent 'Quattro' mirror-less ILCs.

Being able to use a variety of IR filters would be an advantage, as would taking visible spectrum images on the same camera.

Yes, I have several lens-mount UV/IR blocking filters which turn the camera back into a visible spectrum shooter.

I know little (nothing) about the Foveon sensor, are you saying that blue and red channels do not need to be swapped to get an acceptable image from IR?

Correct, that is what I'm saying. The Foveon sensor is quite wide-band - even the so-called 'blue' channel responds to IR if the blocker is removed. I imagine that channels could be swapped but the effect is less obvious than that from a modified Bayer sensor.

Can you post some images of full spectrum and IR images from this camera, please?

Sure, nothing special:

Full Spectrum - un-processed:



The tarp at right is blue.

IR unprocessed - Marumi 700nm probably:



Trying for the Ektachrome look:



Dead tree:



This one is by Seng P Merrill, widow of the late Richard B Merrill - inventor of the Foveon sensor:



Above shots are from models SD10 thru 'SD1 Merrill'. The first Sigma model SD9 only had a dust cover in the lens mount - the blocker was on the sensor like ordinary cameras.