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anyone using cross polarised flash for macrophotography on m43?

Discussion in 'This or That? (MFT only)' started by piggsy, Nov 21, 2015.

  1. piggsy

    piggsy Mu-43 All-Pro

    Just idly wondered if this was something you could do, googled whether this was a thing, found a bunch of articles -

    Getting Started With Cross Polarized Light - DIY Photography

    Taming those Annoying Highlights: Cross-Polarization Flash Macro Photography | NatureScapes.Net – The Resource for Nature Photographers

    About cross polarization and cheap filters.

    Using Cross-polarization to reduce glare and reflections | Photos | Rob Ault

    Most references to it are a few years old now but it's an interesting technique and I was wondering if anyone here had used it recently or had any gear or setups to share for using it on their m43 system. Are the FL600r/i40 class of flashes powerful enough to make it worthwhile to do for a static subject? Anyone had any luck using just a filter over the lens for macro work?
     
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  2. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    They're more than powerful enough, given the working distances the problem is normally being able to turn them down enough rather than not having enough power. Filters work however you will have to mount them backwards on the lights so the light goes through the quarter wave plate before the linear polarizer (otherwise it won't work).
     
  3. piggsy

    piggsy Mu-43 All-Pro

    Yeah, I guess my concerns are more along the lines of -

    1) saw someone mention that to completely kill highlights you're looking at something like ~4 stops of lost light from using the technique - and working in the dark at F22 and a complex diffuser is really pushing things for me already - gotten quite used to the coil whine of a full discharge :D. Although as I understand it the typical application is just the polarising film over the flash and filter over the lens, no other diffusion.

    2) whether it interferes with metering? Seen some comments about wildly inconsistent TTL behaviours with it from DSLR users separate from focus issues their systems suffer from. And also, whether the polarisation stuff has potential to interfere with auto on-flash metering or the TTL command signals if it's at all in the pathway.

    A lot of the demo stuff you see seems to be very much "all on vs all off" but apparently you can actually tune the effect just by rotating the cpl on the lens / the film over the flashes too? Being able to dial-a-highlight like that seems like it would be a cool trick, especially if you had multiple flashes to play with.
     
  4. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    I'm unsure what you mean, the polarisation removes all specular highlights (reflections of the flash). If you use diffusers over the flash you're going to need to put the polarizing film on last (think of the diffusion as the light reflecting/bouncing off/around fibers, it changes the polarization), it's always 1 stop loss of light however depending on the surface of the subject it will appear darker (objects which are highly reflective become darker, objects which are rougher will diffuse the light and change it's polarization - the rougher the subject the closer to the 1 stop loss you will get).

    I have no idea about metering, it depends partly on what look you want.

    If you change the angle of the film/filter it will allow light to leak through, you lose detail in the subject and instead get a reflection of the light source. The advantage of cross polarization is the complete removal of non information (the light source) and instead only light changed by the subject (so it provides a true representation of what the subject actually is).
     
  5. piggsy

    piggsy Mu-43 All-Pro

    OK, so is the loss just 1 stop across the whole system (flash being polarised through the linear polariser film, lens with the circular polariser filter at an angle that eliminates all burnt out highlights/reflections)? That's something I could live with! And yeah, I was kind of digressing there wondering if you actually needed any conventional diffuser if you were polarising the flashes to begin with - seems like no?

    Sorry, bear in mind I've never actually used any type of polariser for any usage case, so I'm kind of starting from zero to begin with and then adding on this specific weird usage to the learning curve :D

    Yupyup. Seen a lot of cool examples of people shooting minerals / glass / plastic / etc that look a lot better than you'd expect from ordinary diffusion too.
     
  6. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    The diffusion can help with lighting as without it's a very direct light source, while the polarization will remove the reflections of the light the more diffuse light will also light the subject from more angles and thus give a different look (a more complete lighting, less/no shadows inside transparent objects).

    Yeap, it can be huge with transparent objects as it allows you to see inside them as the light the camera is capturing is reflected from inside the object rather than on the surface. The main problem with plastics is you can get unpredictable rainbow colour shifts due to the polarized light (depends on the plastic, some are very prone to it).

    In a way it's just another tool however it's something which cannot be replicated easily in post if at all. One of the more awesome/lazy executions of it would be a circular polarizing filter for a ring flash ( OLYMPUS OM T-10 RING CROSS FILTER POL ), I've seen some absolutely amazing pictures taken using it with very vibrant colours.
     
  7. piggsy

    piggsy Mu-43 All-Pro

    Ahh, ok. I'm just trying to get my head around how to combine the two - like - for instance, is there a big difference in how the linear polariser over the flash head would work if it's polarised before it hits the diffuser vs after? If you curved the film to a concave or convex shape around the business end of the diffuser would it polarise it to different patterns? Kind of feel like I just have to go get some of it now to find out :D

    Yeah I'm amazed looking at stuff like that and other cool gear how awesome a setup for macro photography you used to be able to make for OM systems. Seems kind of sad now by comparison in m43 - not only have some of the tools just disappeared, thinking about what they could have done with it by now if they'd kept innovating with it the way they were. 7 different native macros to choose from before you went third party :O
     
  8. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    If you polarize it before the diffuser it won't function, the only light which will be polarized is the light which passes through the diffuser without bouncing (very little) or light which happens to gain the correct polarization on diffusion. I'm unsure how bending the polarizer would work however I suspect it will cause uneven light (one side will be darker than the other, or darker on the edges and lighter on the middle - something like that). Some testing might be in order I suspect.

    It saddens me in some respects (the lack of filters being one) however most of the equipment still exists if you're willing to use legacy 4/3 gear (ttl ring flashes / dual head flashes). Lens wise I generally use adapted rather than native anyway as it offers far more options (I own both enlarger lenses and m42 bellows/helicoid to use them and various OM equipment).

    Generally older higher end macro equipment generates exceptional results, macro lenses are generally designed conservatively and built to much higher standards. I most often use a later generation Olympus OM MC 50mm f3.5 on a speed booster for product shots as it produces exceptional results which are *very* hard to fault (it easily produces moire wide open, the level of sharpness and detail it can capture amazes me every time). I have several OM adapters several of which I have modified to allow wide open focusing (stopping down for the capture when you press the DoF preview button) to allow precise focus, this is as simple as grinding away the lug which forces stop down metering. I also have tilt/shift adapters which allow me to maximize the region in focus with much greater control than purely stopping down, something not offered by any m4/3 lens to date (be aware that not all of them will work on camera models with a viewfinder hump).

    I find conservative lens design often used in older designs can be an advantage rather than a boon as there is far fewer optical defects to deal with and with studio lighting and display boost the slower maximum aperture is almost never a problem.
     
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  9. DanGuy48

    DanGuy48 Mu-43 Regular

    I used to use crossed polarizers on stereo microscopes fairly routinely both with ring lights and dual gooseneck but with Quartz halogen lighting; but flash works the same except it's more tedious to align things. Crossed polarizers are very useful when photographing small wet objects.

    Just as an FYI, to adjust the analyzer (the polarizer on the lens) for dual goosenecks, since it's not so obvious compared to a single source, set your analyzer to some arbitrary reference mark and position both goosenecks for the desired effect. Cover the light from one gooseneck and adjust the polarizer on the other to achieve extinction (maximum polarization effect). Don't move that polarizer or the gooseneck again. Then cover that one and so the same with the other. After that, you can then simply rotate the analyzer to control the amount of reflection on the specimen. I've found that too much removal of reflected light can destroy delicate texture renderings in the sample. Anyway, for those of you doing macro work, thought this might be useful.
     
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  10. piggsy

    piggsy Mu-43 All-Pro

    So I got this up and running and found a few things to shoot with it that can otherwise be a big old shitshow of flash burn even when diffused as much as possible -

    p7230360thfoo69.

    p7280511thc1pvl.

    p7290656thn1p0p.

    p8100824th03oei.

    p8150041thy2rpm.

    p8150053thwcouy.

    p8150055thnaph6.

    p8150062thxtrzf.

    p8170378thtmo1d.

    p8170390th72oy6.

    p8170420thzxrid.

    p8170445-sthstsu4.

    Last one tends to do fine with ordinary flash too but being able to light it that hard without burning the eyes at all was interesting.

    It's a weird technique - you kind of have to juggle it a bit, at a certain point - at least how I have it set up - you end up extinguishing it so hard the flash will try and overcompensate for it again and will often give a tiny pinprick effect of highlights. And it's weird to have the combination of both really diffuse reflected light but you get the stark shadows you'd normally get from having no diffusion at all. Got a lot easier after I hooked up the 2nd flash and was able to hit things from more than one direction. Definitely worth playing with, just a shame there are so few bugs about to hit with it right now.
     
    Last edited: Aug 19, 2016
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  11. retiredfromlife

    retiredfromlife Mu-43 Veteran

    367
    May 15, 2016
    Syndey, Australia
    I have no idea about the technique being discussed, but these photos look very good.

    Regards
     
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  12. piggsy

    piggsy Mu-43 All-Pro

    Should mention I'm using the stuff from my post in the what photography gear did you buy post. The CIR-PL is this hoya filter -

    49mm Hoya Fusion CIR-PL Circular Polarising Camera Lens Filter CPL Polarizer

    adZOZa6.

    and this guy's linear polarising film -

    Polarised/Polarizer Filter Studio Lighting Gel/Film/Sheet Linear Photo 150x150mm

    I don't really do seascapes/landscapes where I imagine the typical use would be. But - doing focus stacks on the Bokina/DCR-250 with it under the i40/fl600r going at full power and having it hold up seems to indicate it works pretty well to me - if you have stuff that is going to flare or ghost, firing off otherwise bare-but-for-film flash heads pointed just away from and a couple of cm from the end of the filter is probably going to bring it out. So something else to go with lenstip's review there.
     
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  13. piggsy

    piggsy Mu-43 All-Pro

    Thanks! Some are stacks, some others are helped by saves from neat image's denoise/sharpening. The lawn beetles in particular - it turns out once you eliminate burnt highlights from a picture of them, you are essentially left with inky blackness, bits of grit, and at just the right angle of incidence it will start picking up reflections of stuff around it. So some of the black bug ones are basically iso200-with-two-flashes shots pushed to about iso6400 on the subject :D
     
  14. pellicle

    pellicle Mu-43 All-Pro

    Feb 10, 2010
    Southport, OzTrailEYa
    pellicle
    @piggsy@piggsy
    never tried it on macro, but it used to be a mainstay of photographing paintings

    do you have any feeling yet if its better or just 'different'?


    sometimes I wish I hadn't thrown out all my kodak publications ... but then as I'm moving house right now, this isn't one of those times ;-)
     
    Last edited: Aug 19, 2016
  15. Carbonman

    Carbonman Mu-43 All-Pro

    Jul 10, 2014
    Vancouver BC
    Graham
    Still have mine from the 70s; compared to the mountain of door hardware catalogs and work reference material, it's nothing to move. BTW my condolences, I'm moving in 6 weeks and am purging and packing every day.
     
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  16. piggsy

    piggsy Mu-43 All-Pro

    Ah yeah, I remember seeing people using cross polarisation for paintings to control reflections from the paint / depth of the brush strokes etc. That's cool :D

    It is "different" rather than better. I think it's possible to use it better than I have been - I made two little snouts for my flashes to concentrate the flash through it, but I'm wondering if it might not be an idea to employ a mix of cross polarised and ordinary light (high power polariser, low power very flatly diffused light). The subject matters a lot for it as well - for some subjects it's no different than using ordinary flash, for some it's very different - but in the cases where it's different you're getting a look with it which you definitely couldn't do with ordinary flash. It also has its own considerations like how narrow the beam from it can be and how hard your shadows can get from it - gives you a new set of concerns over how to light things.

    The FL-600r/i40 flashes by themselves are very close to their limit doing macro at narrow apertures and also doing cross polarised flash. There isn't really one stop in them to spend on this if you're already at F16 and >2x magnifications, and the weight of both of them (plus another light for night shooting) is getting annoyingly heavy. The oly 60 in this case has been a lot better to use than the bokina just from the weight savings. Again I think maybe re-doing the setup with maybe an fl-300r doing a flat normal light and the 600r doing the linear polarisation might be a better setup for usability, setting one up to something so diffused it can't burn anything, and the other to whack it as hard as it can with the polarised light.
     
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  17. pellicle

    pellicle Mu-43 All-Pro

    Feb 10, 2010
    Southport, OzTrailEYa
    pellicle
    @piggsy@piggsy
    I dunno if I've mentioned this before but as to faxing glitter ... of course not, but when you post it do make sure that it is spring loaded to fly up out of the card when opened ;-)

    you will always be remembered for that
     
  18. piggsy

    piggsy Mu-43 All-Pro

    Argh after years of being left up it seems someone finally content id'd the clip of the line off youtube. But. It's from this -

    Frisky Dingo - Operation Snooper Fax

    (the dude who did Archer's older, better show :p)
     
  19. piggsy

    piggsy Mu-43 All-Pro

    Rather than even look at the stupid thousands of of bee and butterfly pics yet to even begin processing I decided to just do something more manageable and find some older cross polarised photos to do instead.

    pa010037thtossv.

    pa060290thkmsdv.

    pa060312th88stq.

    pa120062thgjscg.
     
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  20. zensu

    zensu An Old Fool

    Aug 8, 2012
    Southeastern USA
    Bobby
    Thanks piggsy for posting some great images. I'll have to study this technique but you've shown it can be done. :th_salute: