miguel_mellado

The pop up flash can not change to M manual mode. Your camera is in M Manual Mode. Thus, the preflash is triggering your flash, no the main flash, of course, is not sync.

You require a flash generic (as you have mentioned) or un flash canon speedlite that can change to Manual flash , no ETTL no TTL(and change a fraction of the power of flash, 1/64 for save battery).

These are the solutions, and the others above, olso.

Photonotes.org is very informative web page (the best on canon flash )

Miguel Mellado

I read this, may be help you (Of "Light Science & Magic" Fil Hunter and Paul Fuqua) ):

" Strobes are rated by three basic measurements: watt-secconds( o joules), beam candle power seconds (BCPS), and guide numbers. These are all useful...

Watt-seconds measure the power used by the power supply, not the amount of light coming from the strobe head. The light getting to the subject is also influenced by such factors as the efficiency of the reflector on the strobe head and whatever diffusion material may be in front of it.

BCPS is a true measure of light output, with all elements of the system taken into account. AS an extreme example of the distinction between the two measurements, consdider an 800ws strobe head with 10000 BCPS. If we cover that strobe head with an opaque wrapper, the power consumption (watt-seconds) is not changed, but the light output (BCPS) drops to zero.

Guide numbers are based on BCPS plus the light sensitivity of the film...

Strobe manufactures put much effort into the design of theri reflectors. A strobe head with a highly efficient may light a subject several times as brightly as another head with the same power but a less efficient reflector. These manufacturers continually feel frustrated bu photographers who pay too much attention to w-s , because tht measuremente ignores their efforts to prouce more efficient srobe heads.

Unfortunately, when we place a diffusion sheet in front of a strobe head, or put the head in a soft box, we undo much of the efficiency in the design of the strobe. This is particularly true if we decide to use one of several brands of soft boxes that require us to remove the strobe manufacturer?s metal reflector entirely in order to fit the head into the softbox....

Somebody know how is the difference betwen a auto meter flash IVF and the

meter (only meter)flash IV ? Why " auto "

Thank you and sorry for my english.

Sorry me the english readers.

Manuel, supongo hablas español, yo puedo leer algo el inglés pero escribirlo me es difícil.

Estuve en tu situación hace un año. Dos libros me han ayudado muchísimo: Understandig exposure de Bryan Peterson y John Shaw's Nature Photography. Y creo que ese es el orden para leerlos. También compré otros libros de J. Shaw , Lee Frost, pero los dos primeros nunca te arrepentirás de comprarlos. El de Perfect Exposure no lo he leido pero parece por las referencias respetable.

También hay sitios en Internet donde hay tutoriales que pueden reforzar algunos puntos no bien comprendidos, como los de este site o el de Photozone. Además artículos sueltos en otros lugares muy buenos.

Miguel