Rodrigo e Sena
Não sou técnico mas conheço um pouco das entranhas desses caras, pois já precisei consertar alguns.
Se estiverem dispostos a arcar com os custos de ida e volta para Brasília, posso dar uma olhada nos flashes sem compromisso.
DMZamora, obrigado pelo apoio. Vou me informar sobre o custo é lhe dou retorno. Estou no Norte do Brasil. Qual o seu CEP?
Bem... Segue resposta da Yongnuo :
Dear User,
Thanks for your email!
According to your description, we kindly suggest you to test your speedlite as below:
1. set YN568EX as M mode, take pictures with flash output power from 1/128-1/1, and check if the exposure of the pictures obviously changes;
2. set YN568EXII as ETTL mode, camera aperture as F8.0, ISO100, shutter time 1/200s, keep the shooting distance 3m~6m and take pictures to observe the exposure is normal or not;
3. stand in front of a peice of mirror with camera and speedlite in hand and take a picture of the speedlite in the mirror, observe the picture if the speedlite flashes.
If the test result in step 1 is abnormal, it indicates that the speedlite is faulty; if everything is normal from step 1 to step 3, it indicates the speedlite is normal, and please check your settings correct or not when you use this YN568EX. If the speedlite keeps firing at full power regardless of the power settings in M mode, it's quite possibly the speedlite is defective.
This service center provides technical support and product maintenance. We are sorry that this service center doesn't provide return/replacement service. If your speedlite is faulty and you decide to return/replace it, please contact the seller from where you purchased this speedlite. If maintenance is needed, please ask the seller to help you to send it back to YONGNUO for maintenance. Or, you can send it back by yourself, generally, the maintenance is for free and you should pay the postage back and forth.
Thank you very much for your great support for YONGNUO products! If you have any other questions, please feel free to contact us again.
Best regards,
YONGNUO
Quanto ao teste 1, já havia feito. Em modo M, independente da potência selecionada, o flash entrega sempre a potência máxima.
Já o teste 2, em modo iTTL (uso Nikon) ainda não tentei exatamente com a exposição indicada. Porém, sei que o flash dispara. Como a foto fica sempre subexposta, acredito que não esteja sincronizado.
Para ter certeza, o teste 3 responderá. Farei e postarei resposta aqui.