I've just been having a quick look to try and find a couple of comparative images that show both the advantages and disadvantages of stacking in camera.
The actual images are a bit better than they show up here, as I've compressed them quite a lot for this forum.
The first is of a Common Darter ♀ taken with just a single image focused on the eye; as well as I could anyway.
None of the wing tips are in focus, but I managed to get about parallel to the body for the top shot;
EM-1 Mk2 300mm@F5.6 ISO800 1/2500sec (seems odd settings, but I was out to try and catch one in flight when this individual landed)
Below is the same dragon after it had moved onto a post; same camera/lens/aperture/distance, but an in-camera stack of 8 images, differential would probably have been 4, 5 or 6; I can't remember.
Much more of it in focus, but even with a fast burst at something like 30FPS, you can see the blurring of the tail end where it moved, giving a bit of ghosting, similarly with one of the wings.
exif claims subject distance is 1.8m and using that in DOF calculator mentioned earlier gives a DOF of 1 cm, which ties up about right for the top photo.
The actual wingspan of these is about 6cm wingtip to wingtip, measured from my Field Studies Council life size fold-out guide.
I could probably have done better (as always) had I set the camera to a stack of 15, and a slightly lower focus differential, but I just used what I already had programmed into a button ready to go.
These were taken in August at Taddington Mere, just up the road from me.
Just found this one on Flickr from last year; I think clicking on the image should take you to the original.
This shows the shallowness of the DOF with the 60mm@F2.8 (Subject Distance - 0.285 m from exif)
Bill, very clear evidence of worn out parts. I would assumed you did it hand held then do a burst shots and the rest of stacking is handled by your camera?
I did actually use a tripod and cheap macro rail, which really isn't up to the wight of the 150mm Sigma, but is OK with the 60mm Olympus Macro.
The rail was used to set the distance, to frame the image, rather than for final focusing. The actual high speed photo burst and stacking takes care of the focusing automatically.
The DOF is so thin with this sort of stuff, that hand held, even with the very fancy 5 axis image stabilisation on Olympus, I don't always get a successful stack.
The only reason it works at all, is that Olympus developed a silent shooting mode, where the shutter is held open and the individual shots are taken electronically, almost like individual frames from a video.
I went for a stroll the other day, and inadvertently set the shutter for High Speed Silent. Since both that and my normal low speed sequential, are silent, I didn't realise until I came to download the images from our bimble along the Cromford Canal. 2968 photos in raw+jpg took a while to download and sort.
Since there is this high speed mode available, the camera also has another clever trick up its sleeve.
You can set a shutter release mode, where the camera stores a series of images in buffer, as long as you half press the shutter release.
When you take the final photo, it also save the previous shots, up to the number you've pre-programmed.
i.e. focus on a bird on a tree, wait until it takes off and release the shutter.
Due to our reaction time, one will normally miss the actual start of the flight, but the camera already has it stored in buffer.
Hence the number of excellent in-flight shots we are starting to see from birds actually taking off. ( I should say, that's from other folk, rather than me)
It fills up a memory card very quickly in practice, so you need to get proficient at deleting multiple images in the field.
Posted by Michael Gilligan on 30/09/2020 07:24:01.
That’s an interesting and rather effective image, Bill
Could you please share a single frame from that stack, for comparison ?
Michael, It looks like I misinformed folk originally as I think it must have been a stack of 15 images, though I can only currently find 14 of them in the recycle bin.
If you've seen the video above, you'll have spotted that one can also set a focus differential between shots; in this case I used 1 for a minimum shift between adjacent photos, as the bearings were only 1/8", so I only needed a Depth of Field (DOF) of a bit over 1/16"
If I'd practiced more, rather than what was really just a snapshot to illustrate a point, I think I'd have ended up using a differential of 2, but without playing more I'm not sure.
I'm really not very experienced with this stuff.
Also a couple of basic errors, as I was rushing a bit to complete before we went out for a walk seeking fungi to photograph.
You'll have spotted a blue cast on the bearings which make it look like they've overheated.
I think it was because I left the camera's white balance set to Auto, and the orange plastic lid fooled it.
These two later images were processed individually from raw files from the original stack, and show less colour cast, but I forgot to correct it further before uploading to here; whats left of the bearings is actually silver.
This was 15 stacked images, taken in jpg+raw, but the final result out of camera is a jpg as a result of the in-camera stacking.
I don't normally bother with white balance, as I usually shoot raw, rather than jpg, so it's easy to compensate later.
Inevitably when I shoot these bracketed focus shots, I forget to pre-set to the correct colour temperature.
The second error, was forgetting to reset the differential to 5, so I failed to get full DOF on the later fungi shots.
Front image of stack
Back image of stack
There is a 15th image somewhere, which I think shows a bit more DOF on the lower right hand ball.
It's one of these techniques which needs more practice than I've given it, as there are no set numbers relating to the actual DOF for each of the focus differentials, as it depends on the distance, as well as the lens.
I'd previously had a go with my 4/3s 150mm Sigma macro lens + 25mm tube, which is as sharp a combination as any really, but to get sufficient DOF, I had to stop it down so far that diffraction damaged the image quality.
Anything greater than F5.6 does cause loss of quality in 4/3 or m4/3s, though it's workable OK up to about F11
Being a Sigma lens the in-camera stacking doesn't work, though I could probably have opened up to F2.8 and uses auto bracketing and lots of shots to re-assemble in Helicon or similar.
I don't have a licence for it though, and this was really only for a quick snapshot with minimal post processing.
DOF Calculator is worth a look as well;
Sam, quite some time ago with Olympus (in m4/3s only.)
I think it first featured native from new with the EM-1 Mk2, but became available post release in the Mk1 with software updates.
In some form, it's available in all the EM-1 range and possibly in later releases of the EM-5 &10, though I'm not sure about that.
Focus bracketing, ready for out of camera stacking, has been available for a while too.
In Camera stacking only works with a limited range of lenses, with must be Oly, rather than other manufacturers.
In my EM-1 Mk1, I'm limited to 8 consecutive shots, whereas the Mk2 will go up to 15 (I think); not sure how many in later models such as EM-1x
Nice job Bill. I have made 9 of these 250 style holders for myself. I made 5 of mine so they will take 20mm tools. Instead of the std 12mm lip at the bottom I made it 7mm. Never had a problem with the smaller dimension.
The boring bar holder is 250-204. It has a 25mm ID hole and a 25 OD x 19mm ID split sleeve for smaller bars. I also made split sleeves for 16 & 12mm bars.
Cheers, The original incentive was the knurling tool holder, as I was using an extended nose one I'd made previously.
The Boxford shaper has an 8" stroke, so it wasn't much harder to make four, adding up to a 7½" block.
In my case, I do have a 202 holder with the groove in the bottom housing a larger boring bar; these two are 7 & 12mm.
I don't have any other larger tooling, so these will suffice for the time being, unless I add a couple of dedicated parting tool holders.
A few home made 250 size toolholders for the quick release post on my Warco GH1330;
Four newly completed toolholders to add to my collection for the Big Warco GH1330.
I used most of the machines in the shop on these; Roughed out on the shaper as one block, with the dovetails finished on the Centec mill. Knurled nuts done on the big Warco and finished on the 720 (Myford clone), Toolholders sawn to length on the Denbigh power hacksaw and finished with a combination of shaper and surface grinder.
Final finish with gunsmith's blue.
Not really cost effective to make these, as the originals are about £25 each, but my time's free and it saves getting bored. Also the knurling tool won't fit in the shorter standard toolholder size, such as those three at the front, and as far as I'm aware, you can't buy ones with the through holes to take boring bars.
Unfortunately most older British mills are likely to be obsolete on the parts front now.
Something over 30 years ago, to complement my own S7, I bought a Dore Westbury from Tony, the chap who runs Lathes.co.uk; he used to deal in machine tools back then, as well as his full time job.
It was a well made example, and I've never regretted the choice, particularly since it is one of the rarer long column examples.
I later added a Centec 2B with the Mk3 vertical head.
Again I've never regretted that either, but still have the DW, as it's more versatile for some jobs.
The DW isn't as rigid as the Centec, but actually has a larger workpiece capacity.
The biggest limitation with either, is the table travel lengthways, so have a good ponder on its proposed use.
The DW, being round column, allows one to cheat a bit by swinging the head from one side to the other, to effectively extend the table travel.
The round column is often thought to be a disadvantage, but it can also work in your favour. Swung to the left
And swung to the Right, You couldn't do that sort of trick with a conventional mill
I believe there is a casting missing, the one which is fitted to the bed and supports the wheel adjustment wire when facing.
Having looked through some more documents, it appears that this extra casting may have been available separately to those for the head itself.
I've sent another three PDFs to a couple of folk privately, (Steve & John), one of which has a set of plans for the lathe bed bracket(s) for ML7/S7, ML10 & Boxford
I believe there is a casting missing, the one which is fitted to the bed and supports the wheel adjustment wire when facing.
That would seem to be correct, I have a couple more documents, ex of the Yahoo group, which I will pass on to the two folk that have PMed me already.
I'll deal with them this evening hopefully, but some may need stitching together first.
Steve, should be two documents on their way in separate emails, as one's 6 meg and the other 8 meg.
Check your spam box if they don't immediately show up, as my email address is a bit odd, and is sometimes rejected by recipients.
I thought it unusual to not be able to see any Files or Photo folders listed without joining, didn't realize there were none uploaded.
It would help get more members if the group had some files and photos in the list, pity that the group is very quiet as there must be a good number of DW owners using these machines.
I'll probably get around to uploading some of the old stuff eventually, but the way I had to download it, the filenames aren't all that helpful, so I'll need to associate things together.
There are currently 3 files there, and three folders of photos though, so if you can't see them, you will need to join.
Looks like the old Yahoo has moved to iO groups but not any files or photos listed, perhaps you need to join to see them, link to iO Dore Westbury group, **LINK**
There's not many files up on the new DW iO group; as mentioned earlier, I do have many of the files downloaded from before the Yahoo group's demise if anyone needs anything.
I also have scans of my own build documentation for the boring head and the drawing blueprint available if they are needed.
Steve, I've sent you a PM with my email address.
I have copies of stuff I downloaded off one of the old Yahoo groups, and also the documentation that came with my (already built) one when it arrived.
I still need to scan the latter so it might be a day or two.
Maybe use tungsten carbide PCB drills, available quite cheaply from ebay and other sources in sets of 10 in 0.1mm increments.
Make sure you clamp well, and use a sacrificial steel backing plate, to save the drill breaking through and chipping its cutting edges.
I've just been using one to drill holes in "all hard" hacksaw blades to shorten them for a 9" frame.
Alternatively, if the hole sizes aren't absolutely critical, a new(ish) centre drill works OK, again with suitable close clamping and a backing plate.
NDIY, yours may not have been weak, but mine certainly were for some reason.
After I'd freed up the 10" diameter one, I could slide a 6" diameter piece of cast iron around (the table off my Meddings high speed drill, so a reasonable finish).
After a couple of days with a keeper plate, it's now quite hard work to slide a 1-2-3 block or a 2" square block around on it; I can make it move, but not easily.
I can just lift the 10" diameter chuck up with the end of a rough sawn 50mm EN8 round bar. I certainly couldn't have done that originally.
Whether it/they will improve any more, only time will tell.
This one of the links from my previous link was what lead my to try it.
Do bear in mind the author is from South Africa, so probably isn't referring to Eclipse chucks, and certainly not when he discusses stripping them down.
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