Multi-Shot Oly picture

[BobDavid]

Substation

[Eric Myrvaagnes]

I didn't look closely enough at this one when you posted it in another thread. I needed the "Multi-Shot" clue to examine it enough to see that it really is a composite.

You are a master at the grid composite, Bob. I still can't get how many exposures are included (at least four?), but the step-wise resizing of the substation images is just very effective, giving an overall plausibility to the scene that had me fooled.

Nice work!

Eric

[stamper]

I like the image - nicely processed - but I am not sure if the inclusion of the car helps the image.

[BobDavid]

This is one "click" however the Oly EM-5 II moves the sensor around 8 different ways to make an ultra high resolution photo. I believe the exposure time on this is 1" X 8. So it's not a composite, it's just a super high resolution photo--more like a time exposure X eight. The file size is 64 MP. That's right up there with the big boys--Phase One and Hasseys. The clarity and tonal range is amazing. There is no moire at all in this photo. The best way to achieve moire-free images with of a scene with so much micro-fine repetitive detail, is with a multi-shot camera.

[razrblck]

I'm curious about the results with a moving subject. Like purposefully taking a multi shot image of some action.

[BobDavid]

I'm curious about the results with a moving subject. Like purposefully taking a multi shot image of some action.

In the above photo of the substation, cars drove past the camera during the 8-shot cycle, hence the streaks. Generally, multi-shot is for photographing static subjects. I'll try to post an example of a moving subject sometime over the next few days. It ain't pretty.

[Eric Myrvaagnes]

Gee, Bob! Now you're telling me it isn't the photographer, it's the camera that does all the creative work!   

So what camera do you use to take your wonderful beach triptychs? Or do they just use a different "scene" setting on your Oly?   

I think the cars, stationary and moving, add a lot to the image, contrasting with the solid, immovability of the substation.

[BobDavid]

Gee, Bob! Now you're telling me it isn't the photographer, it's the camera that does all the creative work!   

So what camera do you use to take your wonderful beach triptychs? Or do they just use a different "scene" setting on your Oly?   

I think the cars, stationary and moving, add a lot to the image, contrasting with the solid, immovability of the substation.

Well Eric, not to confuse you, the beach triptychs are from three separate photos that I later composite in Photoshop. And for those photos, I use the same camera. The Oly is capable of single-shot and multi-shot capture. I've been working on a new series, "Stories of the Night." For those pictures, I've been using multi-shot mode for higher resolution and expanded dynamic range. Generally speaking, multi-shot is for taking stills of static subjects. The streaks from the headlights came out well because each of the exposures in MS mode lasted 1/2 second. Since there was a continuous stream of traffic, streaks were recorded in each of the eight exposures.

[Eric Myrvaagnes]

Thanks for the explanation, Bob. I wasn't aware of "multi-shot" cameras. You're definitely the right guy to make effective use of it.

Eric

[BobDavid]

Thanks for the explanation, Bob. I wasn't aware of "multi-shot" cameras. You're definitely the right guy to make effective use of it.

Eric

Thanks, Eric. My first multi-shot cameras were cobbled together from Hassleblad multi-shot medium format digital backs. In those days, I specialized in fine art reproduction and restoration work. The advantage to multi-shot is that it greatly increases the pixel count and does not use Bayer interpolation. So, the color is excellent and moire problems are nonexistent. Now, 8 years later, Olympus makes a multi-shot camera for around $1,000. That's about 35X less the cost of the medium format MS backs of just a few years ago. The neat trick is that the 16 MP Oly sensor produces the equivalent of a 64 MP digital back. Pentax employs multi-shot technology in the K-3 II, but it takes four exposures: R,G,B,G. The resolution does not change, however the color is excellent--Bayer interpolation is bypassed. The Pentax produces clean files and like the Oly, does not have moire issues. Multi-shot is a nifty technology.

[Arlen]

Thanks for posting this image and information, Bob. It's an excellent real-world example of the potential of the multi-shot feature. I just wish my E-M1 had it. I'm betting the "E-M2" will have it. Since they have been lowering the price on the E-M1 lately, I suspect they are preparing for the release of its successor.

[Guillermo Luijk]

Pentax employs multi-shot technology in the K-3 II, but it takes four exposures: R,G,B,G. The resolution does not change, however the color is excellent--Bayer interpolation is bypassed. The Pentax produces clean files and like the Oly, does not have moire issues. Multi-shot is a nifty technology.

Not 100% true. Although avoiding the need of Bayer interpolation eliminates the possibility of colour moire (the most harmful), any sampling digital system is subject to moire unless it implements a perfect ideal AA filter. This happens even when rescaling images down in pp (Photoshop is not specially good at it).

In the Pentax case it'd be monochrome moire artifacts, just like in Foveon sensors. The Oly 8-multishot thanks to the half pixel overlapping has demonstrated such a robustness against any kind of moire I haven't seen a single example though.

Regards

[BobDavid]

Not 100% true. Although avoiding the need of Bayer interpolation eliminates the possibility of colour moire (the most harmful), any sampling digital system is subject to moire unless it implements a perfect ideal AA filter. This happens even when rescaling images down in pp (Photoshop is not specially good at it).

In the Pentax case it'd be monochrome moire artifacts, just like in Foveon sensors. The Oly 8-multishot thanks to the half pixel overlapping has demonstrated such a robustness against any kind of moire I haven't seen a single example though.

Regards

Talk to photographers who earn a living photographing fine art, archiving halftone images, and ultra-fine detail such as textiles. AA filters are not present on Hasselblad, Sinar, and Olympus Multi-shot platforms. I have no first-hand experience with the latest Pentax implementation. As for the Pentax: "Like the K-3 before it, the Pentax K-3 II doesn't include an optical low-pass filter. It does, however, feature an on-demand mechanical antialiasing function," http://www.imaging-resource.com/PRODS/pentax-k3-ii/pentax-k3-iiTECH.HTM

[Guillermo Luijk]

All you said is compatible with what I did, no need to talk to anyone.

http://www.foveon.com/files/Color_Alias_White_Paper_FinalHiRes.pdf

See Fig. 12: image right shows the kind of monochrome moiré (aliasing) a Foveon or a 4 shots multishot sensor like the one in the Pentax (which is functionally equivalent) can produce.

Regards!

[BobDavid]

All you said is compatible with what I did, no need to talk to anyone.

http://www.foveon.com/files/Color_Alias_White_Paper_FinalHiRes.pdf

See Fig. 12: image right shows the kind of monochrome moiré (aliasing) a Foveon or a 4 shots multishot sensor like the one in the Pentax (which is functionally equivalent) can produce.

Regards!

That's quite a leap you are making. Foveon and 4-shot are not at all alike. I've taken tens of thousands of photos with multi-shot cameras and haven't come across moire. Please show some examples. I am curious to learn.

[Guillermo Luijk]

Someone may have taken one million pictures with the most prone to moire Bayer sensor and not experience aliasing artifacts in a single case, but this does not demonstrate moire is impossible with that sensor.

Aliasing is possible in any digital sampling system if it lacks an AA filter, that is well known in the signal processing field without the need to take a single shot. In the case of image sensors it will only be monochrome moire if interpolation is not needed.

How many times will this affect the user in practice? probably few or nearly none. That is why I said your claim is not 100% correct.

Regards

PS: from a Hasselblad owner:

https://captureintegration.com/top-10-things-i-love-about-the-hasselblad-h-system/

"While single shot RGB captures must interpolate colors to develop an RGB file, multi-shot captures make a complete RGB color channel capture (typically Red/Green/Blue/Green), then compile all the color data into a single file. The result is significantly lower evidence of aliasing, especially along straight lines or rounded edges, increased color accuracy, and virtual elimination of moire and color artifacts."

[Bart_van_der_Wolf]

Aliasing is possible in any digital sampling system if it lacks an AA filter, that is well known in the signal processing field without the need to take a single shot. In the case of image sensors it will only be monochrome moire if interpolation is not needed.

I agree with Guillermo on this. In fact, discrete repetitive sampling will ALWAYS result in aliasing that is impossible to reconstruct reliably when the sampling frequency is lower than '2x the finest spatial frequency' (AKA Nyquist frequency) in the analog signal. Sometimes the aliasing will be clearly visible (as moiré or stairstepping), while at other times it will be harder to detect, e.g. amid busy other random detail. Color aliasing will usually be easier to spot than luminance alaising.

Even if the signal can just be reliably reconstructed, say with a discrete sampling frequency between 3x and 2x the finest spatial frequency in the analog signal, it may still look a bit odd. But that can be solved by upsampling.

Color Moiré is exacerbated by the different sampling frequencies and orientation between Green, and Red/Blue filtered photosites. So 4x multi exposure with full sensel shift will improve the color moiré by generating full RGB samples, but the monochrome moiré will remain if the signal is under-sampled. Adding a half sensel shift will generate a very nice roll-off towards the Nyquist frequency, which by the way is two times higher (which already reduced the aliasing risk by doubling the sampling density).

So 16x sampling is a very effective method to increase resolution, and reduce aliasing to almost zero (especially if the sensor uses gap-less microlenses). Unfortunately multi-exposure requires impeccable technique, stationary subjects and solid camera shake reduction with constant lighting. Fewer than 16 samples per image will be somewhat less effective, but already show significant improvement with Bayer-CFA sensors.

Cheers,
Bart

[Jack Hogan]

The clarity and tonal range is amazing. There is no moire at all in this photo.

Yes, oversampling pushes the Nyquist frequency away from moire' generating territory.  Better discussion about this here http://www.strollswithmydog.com/olympus-e-m5-ii-high-res-40mp-shot-mode/