Camera slider/Macrophotography slider - Page 1
Forum section: electronics / projects

author: Achilles
author_rank: Regular Contributor
timestamp: October 27, 2011, 08:27:40 am
content: Hey Folks,I have an idea for a while.....I take some macrophotos and have done some timelapse shots before, what I would like to do again.So it came to my mind to build an automated slide for high magnification photos and focus stacking. I can go up to 1:1 with my macro, but a bit more would be nice. Even with 1:1 it can get hard focus all (even with a veeeery small aperture)The Idea is to build a slide that controls a spindle drive with a stepper motor. I use an old Nikon DSLR with 12Megapixel and DX sensor, so I calculated a Depth of Filed of about 0.3mm at f8 and 1:1 magnification.If I go up to 3:1 Mag this shrinks to 0.071mm (crazy.....). So I want to try if I can get 0.05mm steps accurate, otherwise I choose 0.1mm what should be manageable.The Slide will be made of a spindle drive on ball bearing, like on a cnc-router, with a belt drive with reducing gear. So that is the first useHardware will be a Micrprocessor (thinking of Pic32Mx440), TFT Touchscreen for inputs and fine adjustments (softkeys) and a rotary encoder for course/fast drive, powered by a Lipo (I may take 13,7V Lipo like for RC Toys) and four stepper motor controls.For the Macro slide I just need one, but I also want to use that controller for a longer track (less accurate of course) for a Stop Motion slide with Pan/Tilt, Focus control. Or use it as Slide with Focus and Zoom Control (I think I may just take some rubber wheels which press on the Zoom and Focus ring connected to a stepper motor) because I always wanted to try out the Hitchcock Zoom.I will be in the green in a few weeks so I may take some work for after work with me

author: DrGeoff
author_rank: Frequent Contributor
timestamp: October 27, 2011, 09:37:53 am
content: Not sure what you are trying to achieve here.Why not just use extension tubes or a bellows?Or another trick for really close shots is to reverse your 50mm lens (you can get reversing rings for standard lenses). You lose all the auto stuff, so you need to manually focus and calculate your exposure, but you can get some really close shots.

author: DrGeoff
author_rank: Frequent Contributor
timestamp: October 27, 2011, 09:40:18 am
content: Quote from: Achilles on October 27, 2011, 08:27:40 amDon't use f8 then, I use f42 for most close up macro shots. Never had a problem with focus (manual) or dof at this aperature.

author: Achilles
author_rank: Regular Contributor
timestamp: October 27, 2011, 09:48:34 am
content: Nope it isn't the Magnification I am working on, it is focussing. 1:1 Magnification is achieved at special object-sensor distance and objects have some issues. Number one, at these Magnifications you have a very small depth of field, which you can overcome by shutting the aperture. This means you loose sharpness (at least when you shoot digital) due to diffraction.So you have about 0.3mm DOF. which means focussed at 300mm, everything between 299.75 and 300.15 is sharp, the rest blurs more and more.... A bellow doesn't help here, because you alter the magnification. So you have slides where you can slide your camera forward and backward to bring this small sharp area over your desired object. If you need a higher DOF you could, as I said, close the aperture down or just take a picture, slide the camera back 0.3mm, Take a picture, slide, picture until the whole object is covered and then take the sharp areas of these pictures and stitch them together in Photoshop. As I said, that is called focus stacking.I currently use a 150mm Macro, that allows me to go up to 1:1. With a reversed 50mm attached to that I can go up to about 3:1.http://en.wikipedia.org/wiki/Focus_stacking

author: Achilles
author_rank: Regular Contributor
timestamp: October 27, 2011, 09:54:51 am
content: Quote from: DrGeoff on October 27, 2011, 09:37:53 amYeah, that's what I usually do, but if you increase the Magnification you loose more and more of the depth. You could also use microscope lenses and a bellow for macro. At 1:1.f52 the calculator tells me about 5.2 mm DOF, which isn't very much either. And at least in my setup I see a clear difference between f12 and f42. So for real sharpness I try to avoid really high apertures. My camera has a quite high packed sensor which doesn't help at high apertures, too.

author: DrGeoff
author_rank: Frequent Contributor
timestamp: October 27, 2011, 10:07:30 am
content: Interesting. I hadn't heard of focus stacking before. I can see what you are tring to do now.I shoot animals mostly (reptiles and frogs) so only rarely need to go extremely close (for eyes, toes, scales etc). These subjects wouldn't stay still long enough to try your method on, you get a shot and they move, refocus and reframe and get another shot. Tripods are of no use here either, particularly in the field.

author: Achilles
author_rank: Regular Contributor
timestamp: October 27, 2011, 10:39:58 am
content: Yeah it is really more for indoor use of flowers or so. Even when you are outside and shoot at 1:1 it can get hairy. I had been in Costa Rica this summer and above 1:2 Magnification it wasn't really satisfying because of the wind moving the object...I know hat you mean. I also do a lot about animals (more the creepy crawlers like Anurans, Lizards or Snakes) and you have to move, especially when it is in the wild.I got my frogs at home for studio shootings as well, but I doubt they would hold still for a shoot.The Focus stacking is more for flowers or dead insect, but you can get some amazing footage then. There are people doing it outside, but you have to move quick and carefully then.http://dgrin.com/showthread.php?t=177982

author: Rufus
author_rank: Super Contributor
timestamp: October 27, 2011, 01:05:35 pm
content: Quote from: Achilles on October 27, 2011, 08:27:40 amI'm sure I have seen some automatic 'focus stacking' image processing software on a web site somewhere. I think you just gave it a bunch of images and it analysed them and combined the in focus parts of each.Don't think you needed any precise sequence of images with precise focal distances.

author: Achilles
author_rank: Regular Contributor
timestamp: October 27, 2011, 01:45:45 pm
content: Quote from: Rufus on October 27, 2011, 01:05:35 pmYeah, maybe it's Helicon Focus. A very nice software, but Photoshop can do it on it's own too.... so no extra software needed.You could do it by Hand or trypod (as I have done that before with flowers for example), but it's very hard because of the very shallow sharp area in the picture. You could move your Tripod, but it's difficult because you often change it slightly forward and it's already out of focus.And well, yu could shoot just a bunch of shots with a fast camera/shutter (if possible), but it's not as good.... It's like those handheld Panoramic images. You are happy at shooting, want to stitch them at home and the Software somehow can't find the necessary points.Most Focus stacking shots are made with a spindle drive slider you can buy as accessory, but they are very expensive, too (about 200USD).I just uploaded a quick pic I have taken as demo. It is f16 at 1/400s and 1:1 Magnification. It is a Hibiscus stencil, about 8mm in diameter. When I handhold my camera I already have to be very careful not to be out of focus. For the best sharpness it would be really better to have a fixed position which you can alter in small increments. The optimal sharpness is an infinitesimal small area at the focus point, the rest comes up to the sharpness you tolerate/your eyes can distinguish.You can have a look at the picture here. If you click on it you get it in Full resolution-Ugly-Jpghttp://sachilles.deviantart.com/art/f16-1-1-150-Macro-265541926

author: Rufus
author_rank: Super Contributor
timestamp: October 27, 2011, 02:21:33 pm
content: Quote from: Achilles on October 27, 2011, 01:45:45 pmYes I think you need a mechanically stable silder but I don't see you need a fancy control system. If you can set the camera to shoot continuously then just a variable speed drive on the slider would give you a set of images with enough information. Do you really need to shoot, move by 0.x mm, shoot, move by 0.x mm etc? I presume the shutter time needs to be fairly short to avoid sensor noise so movement during the shutter time would not be an issue?

author: Achilles
author_rank: Regular Contributor
timestamp: October 27, 2011, 02:36:16 pm
content: Quote from: Rufus on October 27, 2011, 02:21:33 pmWell, sure you could just turn a screw and go on. But I think a turn-stack automation would be more accurate help prevent shaking the tripod. If you grab the Slider chances are high that you transmit vibrations to it, even with a very good tripod. Then you have to wait until those are gone. I could also just use a geared motor to drive the mechanical system (as I said there are focussing rails on the market, but rather expensive, too) as you mentioned, but as I said I would like to keep that thing modular. So that I can use a bigger rail for a camera slider for stop motion and so on. Yeah, I could also take a motor there, too, but I'd like to prefer just a driver for a stepper motor.A step shoot step solution would allow me to have some waiting time between the shots for a flash to recycle or so. With a motor I would have to turn the wheel until it fits. There I could just take the steps needed for the focus slide and wait for a delay....maybe more hardware and programming, but I think more flexible, too.There are always lots of ways to get somewhere.....It is not just getting a result, it is also learning about sth. one the way to there.......

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: October 29, 2011, 04:00:26 am
content: I do a lot of macro work- sometimes people even pay me for it! I use CZM when needed; sometimes it's the answer, sometimes it's not. Diffraction is a huge issue in getting truly professional results, and if you close down enough for good DOF, diffraction has usually taken a toll with contrast and sharpness. I think a programmable stage is a super idea, but I wouldn't build the stage. Find a surplus linear stage from one of the usual suspects, Newport, Aerotech, Optosigma, THK, Deltron, etc. They seem to show up surplus often. If you can find a crossed roller bearing stage, so much the better, but they tend to be expensive. Put your stepper motor drive on the stage and you'll have a rigid platform with straight travel and little deflection. To get really good resolution and to reduce vibration, use a microstepping drive. Various motor drive chips have that built in. A really super drive board is made byhttp://www.stepperboard.com/. They cost a bit, but if time is money and you want USB and excellent microstepping, it's worth the $100 or so. If you're as broke as I am, and still have a PC with a parallel port, or happen to have a USB-to-digital port converter (like the nice Measurement Computing stuff), you can do a clever stepper motor control scheme by shifting bits in a pattern left or right for direction. This was published in EDN decades ago and I still use the trick. Obviously you need to be programming in something with a bit shift statement.I use an old Nikon D200 and a 55mm f/2.8 Micro-Nikkor. This works OK to near 1:1, but I also use reversed enlarging lenses on an adapter with extension tubes or a bellows. IMO, extension tubes are way better than a bellows for reasons too obscure to go into here. Everybody wants a bellows because of the cool factor, but too often the minimum distance from flange to lens is too large. You can do really fine macro work with a short enlarging lens (because it's optimized for the distances in question) like an old 25 mm Componon, often reversed if the distances so require. Rigidity is essential and I work only on a cement basement floor. It used to be carpeted and I rarely took sharp photos back then ;-)

author: Achilles
author_rank: Regular Contributor
timestamp: October 29, 2011, 08:15:36 am
content: Hey Conrad,yes that's quite what I had in mind (plus some extra features). Sure, I won't build a linear drive on my own. You can often find unused ones here on ebay or I ask my brother who still keeps contact to some technicians in his old company (cnc, spark and wire ersosion machines).Control via small hand-unit (setup distances and steps) and then go with a driver on a stepper motor.I am using an old Nikon D2x with Sigma 150 Macro. I had seen some really great stuff with microscope lenses and enlarger lenses. You can get really nice Schneider Kreuznach lenses very cheap on ebay....crazy because there are still a lot of People out there who take analog photos. I still have some extension tubes lying around for a try.....and well, if I want a bellow I take my old 1926's Zeiss Ikon Icarette....there it fits in the Style at least

author: Simon
author_rank: Unknown
timestamp: October 31, 2011, 08:01:49 am
content: we just had a talk at our club about macro. Why don't you also consider stopping down to say F22 and using some artificial light or a ring flash to bring to back into reasonable working conditions ? then start playing with electronics

author: Unknown
author_rank: Unknown
timestamp: October 31, 2011, 11:26:42 am
content: As already mentioned, diffraction will reduce sharpness at large aperture values. Plus the difference between f/11 and f/22 in depth of field is quite small.

author: Simon
author_rank: Unknown
timestamp: October 31, 2011, 12:44:01 pm
content: I'm not up on what DOF you get at various apertures, the diifraction will vary from lens to lens so maybe yours won't so F22 nicely,

author: Achilles
author_rank: Regular Contributor
timestamp: October 31, 2011, 08:46:46 pm
content: Hey Simon,when I am out in the field F22 to F45 works OK, but you really can see at my Camera that sharpness decreases after F11 (Nikon D2X with Sigma 150 2.8 EX Macro). I already Use a Tripod and Flashlights for lighting, so the light isn't the problem.As I mentioned before it is just to increase overall sharpness and to get usable results above 1:1 magnification. Up to 1:1 it works quite OK, but you will have to close the aperture quite a lot if you have Flowers or Closeups of animals (Snake-head or so). Above 1:1 it's really getting a bit nasty in terms of DOF. You may google the Canon MP-E 65 Lens, it's made for 1:1 up to 5:1.I think I posted a pic of a snake in the "Dangerous Australia" Topic in General-Section. That had been done on roughly 1:2 and F5.0, but that's a rather extreme example of small DOF.If you have someone around in your club who has a macro lens (real 1:1) you could have a look there. Sure, insects or in wind moving plants or so aren't best for Focus Stacking....so there you still have to step down.So it really isn't impossible to take macros without Focus Stacking (I never said that anyway), but for stills it's a great way to get tack sharp images on high magnification.

author: Simon
author_rank: Unknown
timestamp: October 31, 2011, 09:44:24 pm
content: oh indeed image stacking does give you much more scope on a still image, we were also shown an example of that too, but as you say it has to be a still subject. Lenses do vary a lot so obviously you may not be able to get a good picture above (or below ?) a certain aperture.

author: Achilles
author_rank: Regular Contributor
timestamp: October 31, 2011, 10:48:23 pm
content: Quote from: Simon on October 31, 2011, 09:44:24 pmOh yeah, I also tried focus stacking by hand, but at least you would need a macro rail or so to slide your camera back and forward. Sliding the tripod isn't really fine enough and focussing (altering the magnification....just like you would do on a normal lens) didn't bring best results, too........So I thought about a macro rail (not the cheapy ebay slider) and that's quite expensive....tadaaa, came to automated Stacker.....weird head, I knowAs far as for the Sigma 150 Macro. It is really sharp, even open. It is an 2.8 Lens, but using for macro that extends to 5.6 as minimal Aperture at 1:1. For general portraits (head) it works quite nice at 4.0.outdoors you often have to use flash or so. I had problems this summer when I was taking some orchid-shots due to wind shake. Not that the shutter was to slow and blurred the image. It was more a problem that the wind pushed leaves and so on out of focus. Best thing to have at hand is some clamps to fix what you want to shoot. I took the pics at F16, but even F22 didn't help very much....it gives you an ugly background instead.

author: Simon
author_rank: Unknown
timestamp: November 01, 2011, 06:37:01 am
content: You can actually buy the device you are talking about, but they don't come cheap apparently. Good project idea thought

author: Achilles
author_rank: Regular Contributor
timestamp: November 01, 2011, 11:14:47 am
content: Quote from: Simon on November 01, 2011, 06:37:01 amYeah, I think I had seen that "stack-shot" thing, but it's quite expensive. I think a DIY solution wouldn't be cheap, too....but at least you know what it could be if there is a Problem.....yeah, and learn a bit on working on that and do it like you like it to beFlight is booked, and I will have about two weeks to work on that in the evening without anything else.......could try some things then (TFT Touchpad, Stepper-Driver)