Panasonic Lumix cameras & Post Focus

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Photomicro
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Post by Photomicro »

Jim Haseloff wrote:Really enjoying the discussion - and interested in the shift to 6K mp4 collection of extended focus stacks. I've been using extended focus to image small liverwort plants, an offshoot of our research in Cambridge, where microscopy plays an important role in integrating genetic, cellular and tissue-scale behaviour in plants.

So far, this has meant 4K video capture on the Panasonic GX80, with Olympus 60mm Macro lens, extension tubes and Raynox macro adapter lenses. (More details at: https://www.hackster.io/jim-haseloff/vi ... ope-6b4f76 and https://data.plantsci.cam.ac.uk/Haselof ... index.html. I'm always suprised that there is not more chatter (like this discussion) about the usefulness of the Panasonic extended focus/video modes among macrophotographers.

Given the large array and combination of different lens systems, lighting, and camera bodies, it would be good to identify some kind of standard, readily accessible target object(s) that we could all use for comparison work. Any ideas? - perhaps this has been well-canvassed already somewhere in the forum... I saw that someone here had used a burnt match head as a target - very accessible. Perhaps placing a match head next to the edge of a millimetre ruler might work as a standard? - or something similar, commonplace, with a bit of texture and detail.

I'm still playing around with different lenses, spacing and adapters - so a better reference would be useful. Also, I'd like to make the image capture as portable as possible for field work. I've been using a Vanguard Alta Pro 2+ 263AT tripod with GH-100 pistol grip ball & socket head - which is great, but it should be possible to shrink this - I'm looking at adding short boom arms to mini-tripods. At the other end of the spectrum, there seem to be some opportunities for better "studio" use with cameras that are supported by the Panasonic tethering software. It would be great to better automate the image collection process - so that we can start building extended focus time-lapse movies - with the prospect of HDR and other imaging modalities...

Thanks again for the interesting discussions!

Jim Haseloff
Twitter: @jimhaseloff


Image

Image
Interesting stuff Jim, though I couldn't get your second link to work.

I too have photographed Marchantia gemma cups, and it wasn't until I looked at the photographs that I noticed the tiny hairs (?) around the rim. Probably need to get my eyes tested!

https://www.flickr.com/photos/66189529@ ... datetaken/

I am intrigued that you are adding a diopter lens (Raynox) to the Olympus. Since the 60mm already does quite a high magnification, though you state it is to get greater magnification, you also suggest greater resolution. Have you tested this practically?
regards, Mike.

Time flies like an arrow, fruit flies like bananas.

https://www.flickr.com/photos/66189529@N08/

descall
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Post by descall »

Hello again,
I’m afraid I deleted the ‘cork’ files so cannot provide a bigger version (too tidy for my own good). The below was captured with the Post Focus feature on the G9 with Oly 60 mm macro. The MP4 had 210 frames. The first 10 did not start at the front of the scene, but a little way back and duplicated later frames, so deleted. The final 26 frames focused on objects beyond the rule and were deleted. This is a stack of the remaining 174 frames (Helicon Focus, Method C). Wider out of focus bands occur at the front and back of the stack, plus narrower ones in the centre (the more obvious ones are highlighted in red on image). The ones at the edges can be cropped out and the more narrow ones that appear in the centre are not very noticeable, but mildly irritating. I've tried a couple of different stacks with different scenes and the out of focus banding seems persistent.
Cheers,
Des

Image

palea
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Post by palea »

Hmm, I see smeared patches which don't always correspond to the location marked. When issues like this have come up in the hundreds of stacks I've done with my G7 it's always been stacking software issues rather than the data acquisition done by the camera. There, however, sometimes an interaction where a frame acquired when the lens is slewing focus takes on a keystone shape and has to be dropped or externally aligned to keep from confusing frame alignment and bollixing the stack. I've only seen it on depth discontinuities with Panasonic-Leica 45mm but the wedge-like shape of the softer areas makes me wonder if there might be more of a limitation with your copy of the Olympus 60mm.

Have you reviewed the stack input to assess the potential for such issues? Watching Helicon's frame by frame update can also be helpful to see if it's going off on particular frames. (Another reason I stopped using it is every so often it'd get confused by perfectly fine input frames that would have to be tracked down and culled out or the stack dropped.)
descall wrote:The first 10 did not start at the front of the scene, but a little way back and duplicated later frames, so deleted.
10 is higher than my average but within what I'd consider the normal range. If the pre-scan settles deeper in the image sometimes the first 40-60 frames can be culls, and on a couple occasions where pre-scan chose to end at unusually deep depth it's taken 150 frames for the lens to move to the start of the stack.

palea
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Post by palea »

Jim Haseloff wrote:Thanks again for the interesting discussions!
You're welcome. Thanks for joining us; you'll find your second link on the second page of this thread as well. ;-)
Jim Haseloff wrote:Given the large array and combination of different lens systems, lighting, and camera bodies, it would be good to identify some kind of standard, readily accessible target object(s) that we could all use for comparison work. Any ideas?
To the extent any sort of de facto standard's emerged it's probably ballpoint pens and Ikea Jansjo lights among the threads I've looked at. Printouts have also been used but it appears there's maybe more variability in how printers get ink on a page than among ballpoints.

It also seems desirable to control the stacking method used, though that's probably not especially feasible.

Personally, I'd be happy just with more complete statement of measurement conditions. Images posted answer a lot of the what but often the how is underspecified. In principle it's fairly easy to sort as the rig is probably posted someplace and all that's needed is linking it. However, that's tedious and doesn't happen.

TheDocAUS
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Post by TheDocAUS »

Welcome aboard Jim. This thread and another by gardnersassistant is active on Post Focus: http://www.photomacrography.net/forum/v ... highlight=

TheDocAUS
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Post by TheDocAUS »

descall

The blurring on the left and right sides of the ruler are consistent with AF points either not being present, based on similar issues in some of my captures. I just recompose to make it 5-10% larger and crop out the blurred bits. With the process being automated there is not much you can do.

Not sure on the others.

TheDocAUS
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Noise

Post by TheDocAUS »

A M43 sensor is not the best for low light, prone to having noise in images. So I have been avoiding higher ISOs (not normally over ISO800).

I was hoping the mutli-frames created in Post Focus, when stacked, would mean less noise. I have used such techniques before when stacking astro images. So today I allowed Post Focus 6K video at ISO1600 and ISO3200. No issues with noise in the stacked images.

palea
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Re: Noise

Post by palea »

To my knowledge, stacking algorithms are either noise neutral or noise amplifying. I'm not aware of any which average frames for noise reduction, though in principle it could be done in cases of substantial depth overlap between frames. My G7 is about 2/3 stop behind the G9 and I usually use a noise amplifying algorithm. I go to ISO 1600 routinely but generally try to avoid beyond that, partly as 4k post focus offers less scope for downsizing to average noise than 6k, but would guess ISO 6400 might go with noise neutral stacking and the G9. One could probably get a bit more by scripting noise reduction on extracted frames before stacking.

Cost and manufacturer/system selection no object, full frame's currently around 1.6 stops lower noise than u43 for a given effective aperture and shutter speed. At comparable cost it's closer to a 1/3 stop advantage. At constant subject size the full frame EA is a stop slower, usually associated with about a stop more noise at four digit ISOs. The APS-C options I've checked predictably center midway between u43 and full frame on the tradeoff continuum. One can debate the details of this with 1/3 stop here and 1/2 stop there and MP this and BSI that ad nauseum but the net outcome, more likely than not, is a mild disadvantage to larger formats on these factors. With their additional size, weight, cost, general lack of post focus equivalents or focus bracketing, and lower frame rates where available I'm content with u43. (It's mainly longer macro focal lengths and tripod collars which prompt me to look at larger formats.)

The closest competitor I'm aware of is Fuji's 4k multi-focus and focus bracketing support. I don't follow especially closely but didn't see multi-focus mentioned in a quick check of the X-T3 manual. So it may be Fuji's yet to release a body with both like the G80/81/85 and G9.
Last edited by palea on Mon Jan 28, 2019 3:43 pm, edited 1 time in total.

Lou Jost
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Post by Lou Jost »

For still subjects like these liverworts, automatic focus bracketing seems like a better tool. It guarantees no gaps. And you get RAW files.

palea
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Post by palea »

Lou Jost wrote:For still subjects like these liverworts, automatic focus bracketing seems like a better tool.
If the body has support or if one's working in a studio, it can be a nice alternative to post focus. My G7 has post focus but focus bracketing in the field requires setting up my phone as a WiFi hotspot, joining the camera, and running an app on the phone. So it's only attractive if an image has to happen, light restrictions force ISO too high at the 1/30 minimum for 4k, and a deep enough stack is required it takes more time to bracket the stack manually than to futz around with network setup. The slowdown from post focus to the 7-15 fps limit of focus bracketing isn't necessarily a big ISO advantage. I see the value being more the flexibility in choosing ISO-stack speed tradeoffs, especially in the vicinity of 1 fps. (Perhaps the E-M1X will prove fps competitive with 4k/6k and 4k H if one can afford and wants to carry it. For me it's right out.)

Considering the difficulties that can be had with bryophyte subject motion when collecting stacks at 30 fps you might perhaps come by and explain their stationary failings to the local leafy liverworts and pleurocarpous mosses. Thallose liverworts here are terrestrial and prostrate so I've yet to have a problem with them, though eventually there'll come a day when it's windy enough to set those sporophytes vibrating too.

I end up manually developing raw in a fraction of a percent of images and, lately, in camera jpeg development's been beating external raw developers in about half of those. As such, I'd suggest that limitation is perhaps not so much lack of raw as it is lack of Cinelike D post focus on bodies besides the G9 and GH5 (disclaimer: I haven't checked the GH5 manual on this). In practice it's been a non-issue without either, even in undiffused direct sun. So, sure, raw is better in a Shannon entropy sense but it's reasonable to question the return on investment of the additional processing required.

Lou Jost
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Post by Lou Jost »

focus bracketing in the field requires setting up my phone as a WiFi hotspot, joining the camera, and running an app on the phone.
Wow, that's too bad. With Olympus one selects an easily-accessible menu item and then just presses the shutter. Even if we are only considering jpgs, the quality is better than 4k and there are no focus gaps.

Wind of course will wreck the stack.

TheDocAUS
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Post by TheDocAUS »

Post Focus and focus bracketing does not need the app to work. The app is an optional extra on the Panasonic.

There maybe some confusion on this point. Post Focus is easier to use (by choosing it on the dial), with focus bracketing you need to go into the menu.

gardenersassistant
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Re: Noise

Post by gardenersassistant »

palea wrote:To my knowledge, stacking algorithms are either noise neutral or noise amplifying. I'm not aware of any which average frames for noise reduction, though though in principle it could be done in cases of substantial depth overlap between frames.
Helicon Focus has a stacking method which averages. "Method A computes the weight for each pixel based on its contrast and then forms the weighted average of all pixels from all source images. This method works better for short stacks and preserves contrast and color."

Sharpness/detail is not good with this method, but I sometimes use two methods and retouch the background from the averaged one (or use the averaged one and retouch - paint in - the subject from the sharp one, whichever is easier). You can do this in Helicon Focus and it has a Colour Tolerance parameter for the brush which can help keep the effect of the painting to where you want it to go.
Last edited by gardenersassistant on Mon Jan 28, 2019 4:14 pm, edited 1 time in total.
Nick

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Rework and reposts of my images posted in this forum are always welcome, especially if they come with an explanation of what you did and how you did it.

gardenersassistant
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Post by gardenersassistant »

Lou Jost wrote:Wind of course will wreck the stack.
Not necessarily. I live in a breezy location and work in breezy conditions quite often. For example here is an example from my first session doing post focus for stacking with the G9.

Image
1402 04 P1000442 G9+60 PF6K 25f ISO F2.8 ISO400 1-250 B35,4+i LR7 by gardenersassistant, on Flickr

The post focus video from which this was stacked in Helicon Focus is here at Flickr. As you can see it was definitely breezy (and hand-held too just to add to the fun).

The stack isn't perfect, but then again I don't recall spending a lot of time poring over it and retouching (it was a test image), although I see from the file name that I did do some retouching from one or more individual images. I'm just astonished that it worked at all. I don't often use captures with quite that much movement but there is often some movement of the subject and, when I'm working hand-held, there is always movement of the camera.
Nick

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Rework and reposts of my images posted in this forum are always welcome, especially if they come with an explanation of what you did and how you did it.

Lou Jost
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Post by Lou Jost »

Nick, I was writing about focus bracketing, not post focusing. I am sure that post focus can do better in this regard.

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