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A question for WayneF and other knowledgeables

Discussion in 'General flash photography, lighting, and technique' started by garyosborne, Aug 12, 2009.

  1. garyosborne

    garyosborne Guest

    I am investing some money into cheap manual flash guns and triggers from China, they are cheap Yuongnuo YN460, but i also do not want to entirely move away from CLS. I will probably buy some more Nikon speedlights in the future. I want to be able to mix manual and TTL...to make use of everything i have (if i need/want to).

    Now before you start telling me off, I am aware that this is not really possible if you want repeatable/consistent results, but my question is "Can you trick the system, TO MAKE IT WORK?"...here's the scenario:

    -for ease of use i'll be shooting a midrange zoom
    -i'm shooting a portrait...3 light set up (or 4 with hairlight), Main, fill and back drop

    -Main and fill on TTL, Backdrop and hair on manual.

    This is what i would do:

    -The key in the portrait is to get the faces exposed right (in the simplest form)
    -zoom in to frame JUST the face, use the flash exposure lock to fire the preflashes and set the flash power for TTL
    -re frame, set your manual flashes

    Is this sound? as long as the camera/ subject distance is unchanged. The manual lights should not affect the TTL as it was set without them and they are not really the main light. I am interested in those with more experience in the issues created here
     
  2. General speaking mixing AWL/CLS and "old school" manual flash is a recipe for driving yourself nuts. Having said that, it IS possible to do something like you propose. I've done a lot of experimentation in this area over the years and proved to myself that it just isn't worth it except for ONE possible configuration. If you have an SB-800 on the hot shoe as an AWL commander, you can use the flash PC port to connect a "dumb" flash via a wire and use it for additional lighting in certain circumstances.

    But my question to you is WHY? AWL/CLS is a great system for achieving a high probability of making a good exposure on the FIRST try. For that, it's hard to beat.

    What you're describing sounds more like a studio set up (even if it may be outside) where you're going to do a lot of walking, switching flashes on and off, adjusting the manual power levels, and most likely adding or subtracting some flash compensation from the AWL capable flashes. I would be willing to bet that I can get the shot by setting ALL flashes in "old school" pure manual mode, guessing at the proper fractional power settings, and then zeroing in on the proper exposure and light adjustments after a few tries, chimping as necessary, which would take much less time than routine you propose. An professional portrait shooter with a flash meter and a little experience might be even faster.

    In addition, your subjects might think you went to photography school on the short school bus.

    Bottom line: Fooling around with FV lock, turning on and off various flash units, tricking the system by changing the framing, etc. etc. etc. MIGHT work, but to me it just seems silly. As a young fighter pilot, we called such schemes, "Doing it the helicopter way". (no offense to my rotary wing friends)
     
  3. WayneF

    WayneF

    Apr 3, 2006
    Texas
    What camera? What commander? What Nikon speedlights? How are you going to trigger these manual lights?

    If using the internal popup as Commander, the PC sync connector on D200 and D300 is disabled anytime the popup door is open. AS-15 hot shoe PC adapter wont go into shoe when flash door is open. A SB-800 disables its PC sync port in Remote mode. So no triggering of the manual flashes. Nikon doesnt like that. :smile: And right, I dont think much of it either. Your plan of buying manual lights to use in a TTL system seems questionable. :smile: Why not just use all manual? I understand SB-600s could be that reason, but otherwise (to me), it seems to have no justification at all.

    I think two cases work in a physical way enabling PC trigger - If using a SU-800 commander, the D200/D300 PC sync port should still work. If using a SB-800 on hot shoe as commander, its PC sync port still works (PC works as Commander, but not as Remote). Or manual optical slaves could "work" in the FV Lock case, with the extra flashing. Just seems a shame to have to work like that. :smile:

    It is correct that background light and hair light do not affect the camera exposure values, which are set from main and fill light. Meaning, we set exposure on subject, and background and hair can be bright or dim, and they will look that way, but they dont affect the subject exposure. However, those lights might incorrectly affect a light meter that inadvertently sees them (your TTL case). Not an issue for a manual incident flash meter.

    The zoom might work to ignore the TTL metering of background. Or Spot metering should get rid of TTL BL effect. Or in this plan, it seems bettter to just turn background off to meter subject with FV Lock. Commander meters the groups individually, and one of your concerns is all these other lights triggering while it is trying to do that.

    Careful, FV Lock times out and turns off when the camera LCD display times out and turns off.... you lose the L symbol in the viewfinder then and there is no remembered FV Lock value then (after LCD times out). But there is a menu to greatly lengthen the LCD timeout duration (with battery considerations). Or a helper standing by to "unplug now", and "plug in now" could help.
     
    Last edited by a moderator: Aug 12, 2009
  4. garyosborne

    garyosborne Guest

    Thanks for the replys...you are both right. In the cold light of day this just seems too complex. I guess i was trying to operate in 2 worlds. It seems such a shame to not utilise TTL tech, which is such a strong feature of Nikon but the cost of the strobes means a serious investment. The chinese manual flashes are cheap, almost disposable, therefore a good entry level system for play. I am just reading Hot Shoe Diaries and although i've barely started, it's fantastic. i'll guess i'll learn manual until i can afford to go all out TTL. In fact i just learnt how to use the GN calculator built into the SB800....jees thats a good bit of kit and means i'm in the ballpark straight away. Now if only i knew the GN of the YN460...guess i need a flash meter, but that's the same price as a sb-600....lol gotta love this hobby
     
  5. WayneF

    WayneF

    Apr 3, 2006
    Texas
    This is hear-say, I have no clue myself, but I have heard mention of it being 33 (meters), which the person felt was more accurately used as 24 (meters). 33 m would be 108 (feet), and 24 m would be 79 (feet). That is about 1 stop difference.

    It is easy to determine Guide Number yourself. Your own number will probably be more accurate in your situation anyway, than the spec number which may sometimes be optimistic. The Nikon charts might be a stop optimistic in places too, whenever you have to compensate them.

    Measure off ten feet between flash and a subject (or 6 or 8 or 12 feet, it does not matter, but know your distance carefully). Shutter speed is not a factor, use any shutter speed you normally use with flash. Experiment taking test pictures to find the correct exposure aperture there. Like at full power level, determine whatever aperture actually gives the correct exposure at the measured distance, like 10 feet. Maybe it turns out to be f/11 (your call what is a "correct" exposure, however you want your pictures to look).

    Then the Guide Number is 10 feet x f/11 = GN 110, in this example.
    Could not be simpler. :smile: If you use feet, your GN will be for feet. If you use meters, your GN will be for meters. There are 3.28 feet in one meter, so the GN in feet will be 3.28x more than the GN in meters.

    This is all GN is, distance x aperture number which actually will give the correct exposure. Next time you are at 10 feet, you can compute GN 110 / 10 feet = f/11 again. This is a constant, and then for that flash power, this GN constant automatically handles the inverse square law. So that if some new distance was going to be 15 feet, then the correct aperture for correct exposure at this flash power level will be GN 110 / 15 feet = f/7.3.

    The difficult tricky mathematical part is knowing what f/7.3 means. It happens to be about 2/3 stop past f/5.6, towards f/8. But we can only set the camera lens to f/5.6, f/6.3, f/7.1, or f/8 (third stops), so this is not much issue, it should be clear enough, and it is not a concern about measuring the Guide Number.

    This is how the original guide numbers are determined, experimentally to see what it actually is. That is all there is to it, for any flash. This is demonstrated to be the actual guide number which gives the correct exposure (aperture and distance) for the amount of light that the flash creates.

    The one issue is that if the flash has zoom or power level settings, it will have a new GN for every combination of those settings.

    One other issue that could be good to know in this case is that the f/5.6 that we know is actually f/5.7, and f/11 is actually f/11.3. We just round them off and call them 5.6 and 11, but the precise number in calculations is 5.7 and 11.3. So, maybe plan things out to compute GN using f/4, f/8, or f/16, which are more exact numbers.
     
    Last edited by a moderator: Aug 13, 2009
  6. garyosborne

    garyosborne Guest

    Lol, thanks Wayne....my head is spinning.

    I saw that about the rated and tested GN for the YN460, what threw me off was that the sb600 had a GN of 98 (now i see that number was in feet NOT meters)

    I guess what would be more useful is to find the natural ratio between it and the Sb800 and then make a quick reference table at different zoom ranges. I know that the YN460 would be at least 1-2 stops less power. I am not sure exactly the best way to go about this but my thinking would be to set the sb800 and yn460 side by side (in manual) and shoot comparison shots until the histogram is the same...then i'd know the power difference at a given zoom, rinse and repeat for all zoom levels (there's none on the yn460)
     
  7. WayneF

    WayneF

    Apr 3, 2006
    Texas
    The SB-600 does have a guide number of 98 (feet) at the 35mm zoom position at full power. It has other zoom positions and other power levels with other guide numbers. It has many guide numbers. Guide number chart in manual, SB-600 page 35.

    You could compare one flash with another, and then each 1 stop difference is a 1.414x factor of the guide number.

    Or you could just determine the aperture that gives correct exposure at X feet, and then numerical guide number is determined to be X feet times that aperture.

    GN = feet x aperture number (that which gives correct exposure there).

    This feet x aperture product gives this result:

    2x GN is 2x distance range in feet (for inverse square law).

    2x GN is 2x aperture number (like f/4 to f/8), which is two stops.

    1.414x GN is 1.4x aperture number, which is 1 stop (f/4 to f/5.6 is 1.4x and 1 stop)

    It is all pretty simple when you see that relationship.
     
    Last edited by a moderator: Aug 13, 2009
  8. 73Z1

    73Z1

    Sep 15, 2008
    Sacramento
    Notice a common element?


    Yes, you could jump through hoops and do a lot of work to create extensive GN tables that you must remember to take with you in your kit every time. It could be good info to know as a last resort. On the other hand you could buy a decent used Flash Meter and stop fooling around. Are you going to take a tape measue or marked string with you in every shoot to ensure your distance is always calculated/measured accurately? Or will you guess and chimp, and guess and chimp and ....

    iTTL and AWL are awesome and I much prefer to use the new tools if available. However, I also understand that buying cheapo manual flashes is far, far, more affordable than buying all Nikon AWL gear. In the old film days, we managed to make great portraits with manual systems and no LCD to look at so this isn't an untried avenue. (We did have Polaroids if were were lucky.)

    If you go the cheaper route however, use some of the money saved and get a half-decent used flash meter. I've seen old Gossen Luna-Pro F meters in great shape list on Craigslist and at camera swap meets for an asking price of $75. Less than half the cost of an SB-600. My Luna-Pro F is still accurate and still functions perfectly like it did when I bought it brand new 20+ years ago. No fancy LCDs, but it works with ambient, flash, multiple flash, and flash/ambient mixed exposure. It is so easy to use, you can figure it out without a manual.

    You can shoot and chimp a few times, but doing so a dozen times looks pretty unprofessional. Using a light meter doesn't. Once you get used to moving the light stands or adjusting the flash power based on the meter results, you will soon get a feel for how to quickly setup your lights and meter with accuracy. No tape measure, no tables, no guessing, limited chimping.
     
  9. garyosborne

    garyosborne Guest

    i live in HK and am not about to buy anything 2nd hand or find it. However, 1 shop does carry the Gossen Digipro F, which i beleive is the same as the Luna Pro for about USD280 (a little bit more expensive than appears on-line). Of course, this is an excellent tool, but i question whether it would be a good buy for me. I am not a pro and do no paid work and am unlikely to do so in the near future. While, i would like to achieve pro lit portraits I am more interested in a sort of strobist style where i am looking for interesting effects rather than perfectly balanced light...i guess i'm torn as i can't afford it at the moment. I have read many comments that they are really useful when you start out but as your experience level growths you don't rely on them so much. Let me do some tests with the flashes i have...if i find the YN460 about 1 stop less power it makes it easy to get 2:1 ratio.......

    bugger it.. i'll probably get 1 if i can find a better price
     
  10. 73Z1

    73Z1

    Sep 15, 2008
    Sacramento
    Even though I used my Gossen or a similar unit for years as a full time pro and semi-pro, with the latest DSLRs I find that LCD laziness has taken hold. I shoot and chimp and don't use the Gossen nearly as much. At a paid gig though, it is always available if I have any doubt that I cannot get the exposure set right in 3 tries or less with the LCD. Given your situation and the cost for a new one, I agree that you should wait and see if you can get a feel for your gear without purchasing a new meter. Unless I had paying gigs, I myself would most likely not spend the 280 USD.

    When I worked for a studio, we used a flash meter, but we also had a "standard setup" which was measured with colored marks on a string in case of meter failure. Using the string we could place the main, fill, and background lights at the correct spots for a given setting on the strobe power pack. It was 90~100% accurate every time, and shooting portraits on negatives that was good enough. We also had our own in-house lab, so they fixed the off by 10% part if needed. If you don't mind spending the time working out the distances and playing with the strobes, then save the cash and use it for something that will benefit you more.

    When working with strobes and trying to "dial them in", be sure to fire each one ~5 times before making your measurements. We found that flash to flash output consistency greatly improved after 5 warm ups and was pro qualty stable after 10 firings. For a non-pro it isn't a big issue, but when trying to make a limited color background stay pro quality consistent between subject pictures all displayed in one place, it sure helped.

    Good Luck and Good Shooting!
     
  11. garyosborne

    garyosborne Guest

    Thanks for the advice. I have been living in HK for 4 years and only yesterday i found the most wonderful camera shop, a tiny place that is over run with 2nd hand gear....i have never seen such a selection of lens and accessories, that you could spend ages milling around. They actually had the sekonic l358 for quite a good price (compared to the Goosen). Basically, i need to make a decision to go either all iTTL or all manual....as i am reading the Hot Shoe Diaries i'm leaning towards iTTL. I don't do much studio stuff at all..i use my flash about 85% of the time and for my "out and about" flash use going manual is too much faffing.......iTTL = no flash meter, so we will see. I will still buy a few cheap chinese strobes for fun but what i won't do (but did consider) was to buy 2nd hand sb24/25. 2nd hand sb800 are like hen's teeth here, i can't be bothered with the reduced functionality of the sb600, so i guess i'll start saving for 900's. i'll learn to wing it with my manual flashes, once you get used to Nikons iTTl it's pretty hard to go back, but most importantly NOT AS MUCH FUN. I can't even begin to think what it was like in the good ole days with flash work
     
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