I'm currently in the process of putting together a portrait series and have the chance to go to a couple of vintage events. I've been considering whether to take my 5x4 but I'm mainly concerned about it being a bit slow to shoot portraits of people who may have other things to do (I've mainly been working one to one with sitters who I've made appointments with). The most obvious solution would be to take my Pentax 67 or even *gasp* 5d mkII instead but I'm worried that any work I do in a different format may not fit in the series when it comes to editing time. Does anyone have an opinion or know what critical opinion is of mixing formats in this way?