HDR, well I'll be danged ...

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Originally Posted by tclune

Stupid question: my understanding is that current Nikon cameras are ISO-less. If that is true, why bother taking two photos at all -- why not just take one photo and shift the data, eliminating alignment issues between the two data sets, then do the HDR processing before generating the JPEG at all?

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Search me, so I got out the camera, changed from RAW to jpg (L) and tried setting and using it.

The Controls available (on D7100, in Shooting Menu, under HDR) are:

HDR: Off, On (single photo), On (series), then under that is,
HDR Strength: Auto, Extra High, High, Normal, Low

In use, it does sound like a slow single exposure is taken, without the intermediate mirror movements of continuous shooting (which is disabled if it is on). I cannot say I could hear even two shutter curtain movements, so if it is 'taking' more than one exposure, it is doing that via electronic means in the sensor.
UPDATE: see post 31+32 below; it does appear to be two mechanical shutter activations.

I was testing shooting in to a dingy corner with a bright LED in, not out side in daylight, mentioned FWIW, I was using manual exposure.

Doesn't answer your question, but fills some gaps in my knowledge.

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Originally Posted by george013

You could try to shoot some pictures with exposure bracketing and merge them afterwards. You've the RAW from the individual photo's and can try to analyse the proces. I guess the rough idea is to overlay the pictures and choise that pixel that's closest to the middle,128, so eliminating the extremes. Just a guess.

George

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That's true but most of the HDR programs expect the images to be processed to jpeg and then merged in HDR.

At an rate, that was what I had been trying previously and didn't like the results.

This is one of those cases where there is more than one solution and in-camera HDR does what I would like. I will happily sacrifice raw in those cases. It won't become my normal mode of shooting but, I'm sure I will be using it more in future.

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Originally Posted by tclune

Stupid question: my understanding is that current Nikon cameras are ISO-less. If that is true, why bother taking two photos at all -- why not just take one photo and shift the data, eliminating alignment issues between the two data sets, then do the HDR processing before generating the JPEG at all?

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It's quite possible but ISO is just putting a particular scale on something. You can do quite a lot of processing without knowing the underlying scales of the captured data or by using other scales.

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Originally Posted by Saorsa

That's true but most of the HDR programs expect the images to be processed to jpeg and then merged in HDR..

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The latest version of LR will process multiple RAW images into an HDR composite and produces a DNG file as output.

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Originally Posted by Dave Humphries

Search me, so I got out the camera, changed from RAW to jpg (L) and tried setting and using it.

The Controls available (on D7100, in Shooting Menu, under HDR) are:

HDR: Off, On (single photo), On (series), then under that is,

HDR Strength: Auto, Extra High, High, Normal, Low

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To be clear, single photo means a single serie for 1 HDR result. After one serie,HDR-photo, it goes back to normal. On for series stays on HDR for as long you don't switch it off.
I believe there must also be a setting for the quantity of the photo's.

George

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Originally Posted by george013

To be clear, single photo means a single serie for 1 HDR result. After one serie,HDR-photo, it goes back to normal. On for series stays on HDR for as long you don't switch it off.
I believe there must also be a setting for the quantity of the photo's.

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I think I mostly agree with your clarification George, but I'm not sure why you think there needs to be a 'quantity of photos' setting?
(Since this is nothing to do with whether it is producing the final result from 2, 3 or 5 images, etc.)

As you say, in "HDR (series)" it keeps taking HDR shots (on each separate shutter press), it even stays in that mode after switching the camera off and back on again. Well that's how it is on my D7100, the D750 might differ.

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Originally Posted by NorthernFocus

The latest version of LR will process multiple RAW images into an HDR composite and produces a DNG file as output.

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Yes and with Photoshop, at least from CS6 on, you can open a series of bracketed raw files via ACR and Merge to HDR without any conversion to jpeg. The result can be saved as PSD, tiff, jpeg etc (but not raw).

Dave

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Originally Posted by tclune

Stupid question: my understanding is that current Nikon cameras are ISO-less. If that is true, why bother taking two photos at all -- why not just take one photo and shift the data, eliminating alignment issues between the two data sets, then do the HDR processing before generating the JPEG at all?

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Tom the term ISO-less means that you will get the same noise increase if you increase the ISO setting or if you leave it at base ISO and increase the gain in post (with the same ss and f stop)eg with the "Exposure" slider. But either way you will get more noise in the shadows which is what you are trying to avoid with hdr.

That said, with a camera like the D750, the noise levels are so low that you can get away with a fair bit of shadow lifting in post for an image shot at base ISO.

Dave

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Originally Posted by Dave Humphries

I think I mostly agree with your clarification George, but I'm not sure why you think there needs to be a 'quantity of photos' setting?
(Since this is nothing to do with whether it is producing the final result from 2, 3 or 5 images, etc.)

As you say, in "HDR (series)" it keeps taking HDR shots (on each separate shutter press), it even stays in that mode after switching the camera off and back on again. Well that's how it is on my D7100, the D750 might differ.

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There is a big difference making a HDR out off 2 or let say 9 pictures. Compare it with PP in 8 bit or 16 bit.

George

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Originally Posted by george013

There is a big difference making a HDR out off 2 or let say 9 pictures. Compare it with PP in 8 bit or 16 bit.

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That may be George, but it's not what we're discussing here - we're talking about how the in-camera HDR works, and as I said above, my reference book suggests it does it from two images.

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Originally Posted by Dave Humphries

That may be George, but it's not what we're discussing here - we're talking about how the in-camera HDR works, and as I said above, my reference book suggests it does it from two images.

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I tested my D610 with slow shutter speeds and there definitely appears to be only two shots taken. I can hear the shutter operate between the two shots but I think the mirror stays up.

As far as I can see, there is no control available for the number of shots. I think they need to keep this fairly simple to make it relatively easy to process in camera.

Dave

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Originally Posted by dje

I tested my D610 with slow shutter speeds and there definitely appears to be only two shots taken. I can hear the shutter operate between the two shots but I think the mirror stays up.

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Confirmed, I hadn't gone that slow, but yes, I think I can hear two shutter actuations when using 1/2 second.

I haven't gone so far as to try a test without a lens fitted - I prefer to retain a clean sensor ;)

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Originally Posted by dje

As far as I can see, there is no control available for the number of shots. I think they need to keep this fairly simple to make it relatively easy to process in camera.

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I agree, afterall, although we have seen manual (PP) HDR techniques benefit from a greater number of images, the quick and dirty (but effective) in-camera HDR probably just relies on the HDR Strength setting to determine the number of stops difference between the two exposures - when not set to 'Auto' and (presumably) measured that is.

Whilst I've never been a fan of in camera HDR, it occurs to me that it could be useful for quick shots of people with back lighting, as an alternative to fill flash. As long as the shutter speeds are fairly fast, and with only two shots, a quick in camera HDR could be quite effective in capturing such a shot without subject movement. The beauty of it is that you have instant preview.

Dave

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Originally Posted by dje

Whilst I've never been a fan of in camera HDR, it occurs to me that it could be useful for quick shots of people with back lighting, as an alternative to fill flash...

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Exactly so.

Please note that "works in JPEG only" is a limit of your camera. I have a Pentax K3-II and it shoots HDR pictures and stores them in RAW. But having said that, it is much better to shoot in a "bracketing" mode (i.e. several pictures at the same time, increasing and decreasing the exposure) and then do the HDR magic on the computer. The HDR function in most cameras is more a "cute option" than a useful feature. Again, wether your software can handle your RAW pictures depends on the actual computer OS you use. My iMac using Aurora HDR software can easily handle the RAW pix coming out of my two different Pentax DSLR.

As an aside, the manual for my Canon 7D mk2 on HDR says that if the image quality is set to RAW, the resulting image will be saved as a maximum quality jpeg. If the image quality is set to RAW + Jpeg, the image will be recorded to the jpeg image quality set. By this I assume that the original raw images will be preserved.
In hdr shooting images are shot with differing shutter speeds, even if the camera is set to shutter priority or manual.

Following is an in camera hdr of a very dark cave looking out to the river at Moira Gate, in the Oparara Gorge.

http://i66.tinypic.com/2n9ylx0.jpg

And without HDR

http://i68.tinypic.com/28ktv5z.jpg