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Flash with Manual Lenses

Discussion in 'Lighting Forum' started by Jakob F., Jul 9, 2011.

  1. Jakob F.

    Jakob F. Mu-43 Regular

    88
    May 18, 2011
    Copenhagen, Denmark
    Hi,
    Any quick tips for using flash with adapted lenses? I have a number of adapted lenses that I use with my E-P2 and recently bought a second-hand FL-36 -but I've never used a real flash before, so any quick and dirty tips for setting up camera and flash and lenses to get the most from each, would be greatly appreciated!
    If it's relevant, the lenses are Fuji Fujinon 25/1.4, OM 50/1.4 and OM 85/2 -and I'm going to need the flash for indoor low-light shooting. I've even made myself a genuine DIY bouncer/diffuser, but I can't upload pictures via the mu43 iPhone app :(

    Thoughts?

    Best regards,
    Jakob
    Jakob
     
  2. I tested my Olympus FL-36 on a GH2 using a Vivitar 28m. I set the flash for auto TTL and the camera for aperture priority. It seemed to work reasonably well with good exposure from about 4 to 15 feet, not adjusting anything but the focus. I posted a bunch of these at https://picasaweb.google.com/homershannon/2011525FlashTests?authkey=Gv1sRgCNTQy8StuP6RhwE with some comments.

    That said, I was at an event last night using the Panasonic 14-140 lens in P mode and the same flash. Anything under 5' was terribly over exposed. Guess I haven't fully figured out flash photography yet!
     
  3. Ned

    Ned Mu-43 Legend

    Jul 18, 2010
    Alberta, Canada
    Whether using manual lenses or native lenses, you will be able to use the flash with the same full features (ie, Auto, TTL) as long as you are inputting all the correct metering values (ie, Aperture size).

    However, I personally prefer to use all my speedlights on manual. I find TTL Auto to be nothing but a pain since I never want to shoot bare flash at my subject, and that is how the camera is made to meter. Of course you can play around with Exposure Comp on the flash to account for light modifiers, and be careful about setting your distances, focal lengths, ISO values, etc. I find that setting up Auto takes more time than simply inputting manual power settings and going by experience to know how much to compensate your shutter speed for the flash. Plus, if you are using multiple flashes (especially at varying distances), then you need to use the Remote Commander to properly set up TTL.

    I don't think I'd be good to teach you a quick and easy way, but I go by my experience to know how much light intensity I want (ie, 1/1 power, 1/2, 1/4, 1/8, etc) out of each light (set your power on the flash, not on the camera), and then in Aperture Priority mode I use Exposure Compensation and Aperture to account for the extra light. For instance, maybe 1 light at 1/1 or 2 lights at 1/2 might need -3 EV at a specific distance from the subject, then adding another light at 1/1 power will require -3 EV plus stopping down the lens to f/5.6. If the light intensity is too strong for both Exposure Comp and stopping down the lens (usually when I'm using brighter lights like studio strobes), then I go into Manual mode and manually set Shutter Speed as well as Aperture (usually setting a shutter speed to match max sync speed - ie, 1/200s for the E-PL2) then stopping down the aperture as much as needed for proper exposure. For instance, with two studio strobes in softboxes shooting small products, I might set my shutter to 1/200s (yes, the manual and camera says max sync is 1/180s, but I have never seen the shutter curtain appear at 1/200s on my E-PL2) then play around with the f-stop between f11-f16 until I get the right exposure.

    These are all very broad examples, as only experience will tell you what exact settings you need. Keep playing around and learn, chimping along the way to get it right. Keep in mind one thing before you start chimping for exposure though - ensure first that your LCD is set to the proper Monitor Brightness setting (look in your manual if you don't know how to set that) to match what the file looks like on a standard computer screen. Some cameras ship with LCD brightness way too bright (I've never had one yet which was too dark) which will result in underexposed images when you upload them to your computer - and my computer monitors are calibrated pretty well, coming from a background in Visual Communications.

    There are 4 main factors which determine the overall light intensity to compensate for - type of modifiers on each flash, distance of flash from subject, flash power setting, and of course the number of flash units used. When you start using flash enough, it will soon become intuitive to you what flash power, aperture, shutter and/or Exposure Compensation values you need.

    Or you could use TTL Auto... Quite frankly, I couldn't even tell you how to do that effectively. ;) I hope this little spiel helps you better understand the relationship between the settings, whether you decide to learn manual flash setup or not.

    You did say that you are already using hand-made diffusers and bouncers. That's a good sign that you've got some understanding of how the light works and are on your way to manual flash setup. When you start modifying your lights like that, you are throwing TTL out of whack and manual settings end up being easier than compensating for your modifiers with TTL.
     
    • Like Like x 1
  4. Jakob F.

    Jakob F. Mu-43 Regular

    88
    May 18, 2011
    Copenhagen, Denmark
    Thanks for the input, it's greatly appreciated!

    I think I'd better clarify a few things, though.
    I'm only using that one fl-36 unit I've got, mounted on-camera, and mainly for family get-togethers, birthday parties, and other parties. Indoor, poor light, where wide open isn't always a possibility, since I'd like to have more people in focus and not only the nose of the guy closest to me ;v)

    (The diffuser was made, mainly because I could -and I've read somewhere that it eliminates red eyes?)

    So I was thinking:
    Since the lens is manual, the camera can't tell neither aperture nor focal length, and therefore can't communicate it to the flash and the flash can't compensate and output the right amount of light.

    So... I figured there was some sort of rule of thumb, like "if your focal length is this and your aperture is that, divide by cucumber and enter this manually in your flash"
    Say I want to use the 25mm /1.4 @ f5.6 or 8 to get a decent DOF, plus I'll need a shutter speed that allows freezing the kids playing -what would I set my FL-36 to?

    Is there even such a formula? At some point, someone must've sat down and thought "well, now that I've experimented the life out of 20 flash units, this is what I deduct" -or something like it ;v)

    Links to tutorials are just as welcome as your personal input, and just as appreciated!

    Thanks in advance!

    /Jakob
     
    • Like Like x 1
  5. Pan Korop

    Pan Korop Mu-43 Veteran

    479
    Mar 31, 2011
    Phare Ouest
    The old GN for Guide Number rule.

    Seems you ask for the Guide Number (GN) rule.

    Ok: you need to know the GN or your flash. Since it's called FL-36, I presume it's 36 (in meters) for ISO 200. Better check your user's manual for the documented GN.

    The GN is equal to N x D, where N is the applicable aperture value (2, 2.8, 4, 5.6, etc.) for a distance D.

    This means that, in a "standard reflective room", with your camera set at ISO 200 and strobe at full manual power (GN 36), for a subject at 4m, you have to set the f/stop to 36รท4 = 9, i.e. between f/8 and f/11.

    If the room is small, white walled, with not too high a ceiling, close down 1/2 stop--here, f/11.
    If you're outside in open space, open up by 1 full stop--here between 5.6 and 8 (6.3, 6.8).

    Too complicated? Start a hunt for automatic, GN-coupled legacy lenses :biggrin:
    • there's one from Nikon (Nikkor 45/2.8 GN), the famous original Nikon pancake, at around $200 on eBay. Surprisingly good on :43:
    • There's supposedly a full series from Topcon named GN Topcor, but the only common one is the 50mm f/1.4 (ca. $300). Never tested one.

    They work the same: set the ISO and GN on the lens, and when you adjust the focus, the correct f/stop automatically follows.
     
    • Like Like x 2
  6. Ned

    Ned Mu-43 Legend

    Jul 18, 2010
    Alberta, Canada
    Depends largely on what kind of modifiers you use, and how many stops of light it eats up. How much ambient light is available also makes quite a difference. With a heavy, soft-light diffuser like mine I would be need about 1/1 or 1/2 power to get a 1/160 shutter speed for a kid's full-body portrait at 25mm focal length, indoors with muted lighting. Or something like that. ;)
     
  7. Sammyboy

    Sammyboy m43 Pro

    Oct 26, 2010
    Steeler Country
    I just tried this on my E-P2 with an OM Zuiko 50 / 1.4 and the FL-36R attached in the hot shoe. All exposures were very good.

    Camera: set on Manual, shutter speed set on 1/160, ISO set on 400
    Flash: set on TTL Auto, flash zoom control set at 17mm (42mm zoom setting will allow for slightly greater subject distance)
    Lens: various exposures with aperture setting from f1.4 to f8
    Subject distance: 15 feet
     
  8. Jakob F.

    Jakob F. Mu-43 Regular

    88
    May 18, 2011
    Copenhagen, Denmark
    Sweet, and again -thanks for the input! It's really helpful!

    One question for Sammyboy, though -if shooting with a 50mm -why then set the flash zoom to 17mm? Shouldn't the flash zoom setting reflect the focal length? Or am I missing something?

     
  9. Sammyboy

    Sammyboy m43 Pro

    Oct 26, 2010
    Steeler Country
    Only because I failed to reset it from a previous shot using a different lens. You may want to keep the flash zoom slightly less than the effective focal length of the lens to avoid light fall-off on the edges. You can do some of your own testing to see what suits your liking the best.

    Please note, the ISO was 400 not 200, I made a typo and edited it, but after you read my post.
     
  10. Jakob F.

    Jakob F. Mu-43 Regular

    88
    May 18, 2011
    Copenhagen, Denmark
    Aah, okay -makes sense! Thanks for clarifying :)
     
  11. Ned

    Ned Mu-43 Legend

    Jul 18, 2010
    Alberta, Canada
    The E-P2 has an ISO 100 setting and although ISO 200 is the base ISO of that camera, the ISO 100 setting can be useful in using flash as it will help you to avoid going over max sync speed when using a lot of light.
     
  12. thearne3

    thearne3 Mu-43 Top Veteran

    807
    Jan 28, 2010
    Redding, CT USA
    If you want the 'full monty' on manual flash, check out Strobist: Lighting 101. This the first installment of a truly wonderful, experiential approach to manual flash.
     
  13. Jakob F.

    Jakob F. Mu-43 Regular

    88
    May 18, 2011
    Copenhagen, Denmark
    Sorry about the prolonged silence -and again, thanks for all the input! Now I'll spend some time reading the manual for the FL-36, and try to get something useful out of it. Guess it just takes some practice ;v)

    Cheers,
    Jakob