On Camera Flash Diffuser Not So Good On Nikon D80 Trouble With Fill Flash Vs. Outdoor Lighting Nikon D80 ?

Trouble with fill flash vs. outdoor lighting Nikon D80 ? - on camera flash diffuser not so good on nikon d80

I have a bounce flash SB-600 that I have with my Nikon D80. I almost always shoot with my 50 mm lens Nikor 1.8. Mostly with flash, because I can not number 1 is required for that purpose, and number 2 I think it is ugly to use them outdoors Flash, because we can bounce back. My question is that rare time I use the external flash, would I still blur to 2.8 again for the background, but if you turn the flash of a camera is immediately "flash mode, and only you have the shutter speed make up to 200th This poses a problem, because sometimes I throw a 3000 in order to shoot at 2.8 tonnes, it is light, without a SUPER photo most exposed. Thus, when using the flash, since they can only the closure time 200 to ensure the quickest, I suggest the way for every 10 or 12 in order to obtain an image that is overexposed, but then I lose all my depth of field. I tried the EV and ISO at the lowest agency and do not function well. Is there a way to dWhere? In addition, flash, because you do not bounce outside, a station for a good buy that I will have the same effect as the exterior?