Home » , , , , , , , , , , , , , , , , , » Why it is cheaper to buy flash gels rather than to balance the white in post production - Perché conviene comprare le gelatine per il flash piuttosto che bilanciare il bianco in post-produzione

Why it is cheaper to buy flash gels rather than to balance the white in post production - Perché conviene comprare le gelatine per il flash piuttosto che bilanciare il bianco in post-produzione

Some cool flash photo images:


Why it is cheaper to buy flash gels rather than to balance the white in post production - Perché conviene comprare le gelatine per il flash piuttosto che bilanciare il bianco in post-produzione
flash photo
Image by funadium
This small alley in Cervo (Imperia, Liguria - Italy), named "Via XI Febbraio", is on the East side of the Corallini church.
The house on the right is yellow.
The main light comes from the yellow sodium lampposts in the main square, and the end of the alley is totally dark, so I decided to give it a pinch of light with the flash.
Here is an acrobatic exercise in white balance... of course the original shot was saved as RAW (are there other modes?).
If I balance the white to have a good background the foreground becomes too yellow, while if I balance for the foreground the background becomes blue, as you can see in the small details.
Some hours in post-production, using RawTherapee and GIMP, with half a dozen of masked layers, gave me an almost decent result.
If I had to pay myself (and not even at photographer tariffs, but at the wage of an unskilled "deputy bricklayer", maybe clandestine) the cost of the manpower to fix this photo will be far higher than that of a set of gel filters for the flash, to give the flash light the same color of the main one.
Conclusion: if you have to shoot with different light sources and some strobes, it is faster and cheaper to use gels.
Who want the XCF GIMP image with all the masked layers (148 Mb) can mail me.

Lens: SMC Pentax-M 28mm F2.8" "28/2.8 @ f:8
Camera tripod: Manfrotto 190XPROB
Flash: Pentax AF400T at full power, hankie as diffuser
Trigger: cactus like
Flash tripod: myself
Camera trigger: my wife


Questo vicoletto a Cervo (IM), chiamato Via XI Febbraio, si trova sul lato a levante della Chiesa dei Corallini.
La casa a destra è gialla.
La luce principale è quella dei fari gialli al sodio della piazza principale, e la fine del vicolo è completamente buia, quindi ho deciso di aggiungere una pennellata di luce con il flash.
Ecco un esercizio acrobatico nel bilanciamento del bianco... naturalmente lo scatto originale è stato salvato in RAW (ci sono altri modi?).
Se io bilancio il bianco per avere un buon sfondo il primo piano diventa troppo giallo, mentre se bilancio per il primo piano lo sfondo diventa blu, come si può vedere nei dettagli.
Alcune ore in post-produzione, usando RawTherapee e GIMP, con una mezza dozzina di livelli mascherati, mi ha fornito un risultato abbastanza decente.
Se avessi dovuto pagare la mia manodopera (e non a tariffa da fotografo, ma al salario di un vice-manovale, magari clandestino) il costo per sistemare la foto sarebbe stato di molto superiore al prezzo di un set di gelatine per il flash, da usare per avere la luce del flash dello stesso colore della luce principale.
Conclusione: se dovete fare una foto con diverse sorgenti luminose ed alcuni flash, è più rapido ed economico usare le gelatine.
Chi volesse l'immagine XCF di GIMP con tutti i livelli mascherati (148 Mb) può mandarmi una mail.

Ottica: SMC Pentax-M 28mm F2.8" "28/2.8 a f:8
Cavalletto macchina: Manfrotto 190XPROB
Flash: Pentax AF400T a piena potenza, fazzoletto come diffusore
Trigger: tipo cactus
Cavalletto flash: io
Trigger macchina: mia moglie


freeduino wireless 4 channel TTL flash controller
flash photo
Image by fotoopa
Wireless remote control receiver for 4 channels. The wireless unit is the RFM12B module, the hardware is the freeduino board with the Atmega168 AVR controller.
Software is ready and tested on the Intronix logic analyser and very soon the transmitter side will be connected to see if both modules works.
The receiver have 4 TTL flash controls output via an ULN2803 driver. Multiple flash tables (for SB-80-DX, SB800, SB29S) are into the AVR controller to control the different flash types. Power will be 3 AA batteries giving 3.6V. A small diode in serie is used to adjust the max level because the batteries gives 3.9V at the max charge.
I wait now for the Nikon TTL flash cables to build the receiver into a small box.

See also photos:
www.flickr.com/photos/fotoopa_hs/3798474398/in/set-721576...

www.flickr.com/photos/fotoopa_hs/3778250766/in/set-721576...

Update: 2009 Aug 13

The Freeduino receiver module works! I use the max transfert speed of 115 Kbaud. The 4 flash channels are driven correctly. The SPI speed is the same as obtain by the Hardware version. I need 23 us to tansfert 16 bits data via the SPI. Now I need to implement a few extra commands to change remote the powerlevels and the EV steps. But this is only a few software lines to add. I wait now for the Nikon SC-27 TTL connection cables but normal they will furnish next week. I need also a small box to mount the receiver module and batteries.

Next planning is to build the transmitter also with the Freeduino print and the AVR controller. But there I need an extra LCD display to enter the remote parameters for the receiver. At the end of this year, the transmitter will be integrated into the CPLD unit because there is also a display and buttoms on this unit.

Update 2009 Aug 18:
For the TX module see:
www.flickr.com/photos/fotoopa_hs/3819906473/
The first interface routines are written, the LCD display works now. The next days the RFM12B module as transmitter will be tested.


receptor al flash
flash photo
Image by Leon www.fotosdepuebla.org

 
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