you forgot 'more expensive'... kakakaka

i'd get the TTL... just pay a little more for the flash to 'work' for u.... not u work for the flash. i know a lot ppl will say, use manual is more pro... to me, they are just pro wanna-be. TTL are design to make ur life easier, not harder.

of coz, studio shot are diff, as u have all the time to setup ur lighting and composition, doing it manual give more consistent result....

but in event or birthday party, or wedding, ur mind is so consume into taking photo, u wont have time to think what manual power to use... TTL FTW.

Alex, honestly, if u have the money to spare, go canon flash. the eTTL is more accurate then nissin/YN ttl. or there is another 3rd party with eTTL is the METZ (slightly more expensive 3rd party, but cheaper then canon ori).

i think u have a question in mind that need answer;
when u use M mode on body, the flash TTL still Will Work. meaning it will still find the compensate power level to fire. so u can set M for consistent ambiance light, and let the flash(ttl) find the right amount of light to lit ur subject.

but if u set flash to manual, u at least need some experience and guts to use it. because, there might be chance it will go under or over which requires a LOT of work of Post processing, might get a proper AUTO TTL and reduce the post processing.

there is many, but advisable that u head to Sony Thread as more people can help u there.

this is Very Subjective. because it will be affected by shutterspeed, aperture, and iso.

D40 has good iso till 800, and assuming standard 5.6 lens. shutter of 1/60(which wont affect flash power yet)... it may reach 15m (example, any given flash)
D7000 has good iso till 3200, and who know u using F2.8 lens, shutter of 1/60.... the flash may reach up to 25m because given sensitivity and light absorb rate has increased.

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Added on September 28, 2010, 5:34 pmwhy not? if given 580ex2 has GN58 (in meter) means at iso100, F1, 105mm zoom, it reaches 58meter.

let say a 550D has iso3200, F5.6, the flash CAN reach 58meter. 15 meter is nothing.

(apply same way if u are Alpha user, with A550 +F58)

or even F20 (sonyflash) can reach 20 meter with iso3200, F5.6

This post has been edited by ieR: Sep 28 2010, 05:39 PM

nikon are in feet (read my reply to Goldfries.

yea, noone shoot taht far, but the power of the flash is need when u do bounce sometimes, GN40~ (like 420, F42 and SB600) are not enough to bounce a 2 industrial story ceiling... or huge ballroom. or fighting against daylight/backlight photo, u do need that 'power' but not the range.

the GN is a way to show how far the power can do, not a comparison of distance... but power a lot ppl misunderstood the need of GN58m.

Goldfries: nikon GN is in Feet Canon and Sony uses Meter GN.

SB900 has 132GN. (it canot be 132 meter so that is in Feet.) so its possible that GN58m...

but the Gn feet to M cant be converted directly, because the 132GN is at 35mm iso100. some trial and test show that SB900 fire till 57meter, on 200mm iso100

in other words, the F58 and 580ex2 is more powerful then SB900 (people got mislead that sb900 is more powerful or further in range because of the 200mm zoom)

(the mm refer to flash zoom, not lens zoom. and all GN is sensor sensitivity upon using F1 lens)

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Added on September 28, 2010, 6:32 pmbut our flash is a 50+ watt strobe, we cant compare to a 100watt or 200watt studio strobe... those, if set properly, with proper zoom design head, it can reach pass 100meter GN easily

This post has been edited by ieR: Sep 28 2010, 06:32 PM

it could be, i dont know exact value of 866 GN, but most figure i saw online is GN60 (m)... but then, those several meter makes no diff, because the distance drop drastically at iso100, F5.6 (that is 5 stop) meaning, from 1/1 drop to 1/32

This post has been edited by ieR: Sep 28 2010, 07:00 PM

well, its not distance sensor, but just a TTL sensor with Lens-distance information being calculate intensely(well noone knows the real formula LOL) which they market as i-TTL (nikon) or (e-TTL(II) for canon and ADI for sony)

3rd party flash does not have the intensive formula to retrieve distance as key to accurate exposure (hence why we always encourage people to get original brand flash), but Metz flash (more expensive then Nissin) has license for i/e TTL and ADI.

the TTL(pre-flash) will calculate how much light is needed to brighten up the photo, but another thing u have to know is, the TTL relies on the Metering Mode u choose. if u picked spot, the TTL will only fire as much to balance the Ev on the spot only, ignoring all other space(frame). if u pick Multi/wide/(other word mean whole frame) metering, the flash might fire stronger to fill the room with light, that might cause ur subject to be a little brighter then usual.

understand the whole basic of ur camera from PASM to Metering EV(aperture,shutter and ISO - the exposure triangle) then only learn flash.... or u can just use AUTO all the way

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Added on September 29, 2010, 12:26 pmThis post has been edited by ieR: Sep 29 2010, 12:26 PM

ever consider Metz? http://shashinki.com/shop/metz-shoe-mount-...facturers_id=94

its less power then the model u mention, slightly more expensive, but it has better "e-ttl" accuracy. those model u mention only has TTL which is not consistent. if u wan to go serious with wedding and event shooting, i really advise metz or canon flash, because if u buy those, u will struggle to get right photo then 2-3 month later u surely wan to upgrade to canon flash ohhh...

or Metz more powerful model, http://shashinki.com/shop/metz-shoe-mount-...facturers_id=94 in my opinion, this flash is better then 580exII, for the frontfill is very useful(there is another 2nd flash below the main head)

Maha Imedion (2100mAh (oldmodel), (new model) 2400mAh)
Sanyo Eneloop (2000mAh)

these 2 are highly recommended. the new Imedion has 2400mAh(min) are not Hot Seller! grab one now from Shashinki! promotion

This post has been edited by ieR: Sep 29 2010, 06:30 PM

TTL is a sophisticated math done by the camera body with Lens attach.

there is, way to inject new variable (settings) into the sophisticated formula for TTL to mess up the whole lighting if u dont know what u are doing.

yup, but the consistence, not 100% reliable. it works and may give weird result sometimes.

faareast, i dont have nissin, not sure how nissin works or does it has TTL for WL mode. because nissin was optical trigger, not CLS trigger signal, i doubt it can run TTL

kent: i think my answer was weird to farreast... @.@ i think i was saying yup to his question that can WL use TTL.... then 2nd part, i am blur...

i dont have phottix aster, but if the phottix aster
i. uses nikon hotshoe mount connector
ii. support E-TTL

should be can... else, it cant. i amnot sure, check with phottix help file or website.