I don't think I would be able to shoot 3x macro of anything that flies. :) It is hard to find where the bug is as it is. I ordered Vivitar tubes from B&H, passing electrical contacts can only be a good thing and I did not notice any problem with P-TTL at 1/4000 so that is fine with me. If I move significantly inside 1/4000 the whole image will be blurry anyway. I can easily set my D to use TTL if I want by setting aperture away from A position on the lens. I also ordered some male to male rings so I don't have to use duct tape. I just hope this will be enough extension to get rid of the vignetting.
Irony is, I sold my Pentax auto tubes after I got Tamron SP90 1:1 macro. I did not think I would need anything better than that until I tried to shoot an ant which was 2mm in size and I wanted to see how his eyes look magnified. I was able to get the picture of the eye but everything else was out of focus because of f2.8 as that was the only aperture that did not have vignetting. :) I also thought that Tamron SP90 has enough built-in tubes as it is so why add more and move the focus inside the lens. But it looks like there is another purpose to tubes except moving the focal point closer to the lens. ----- Original Message ----- From: "Jostein" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Wednesday, May 11, 2005 3:37 PM Subject: Re: reverse mounting lenses > You're right, Leon. > I forgot to think about flying insects. :-) > Jostein > > ----- Original Message ----- > From: "Leon Mlakar" <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Wednesday, May 11, 2005 9:14 PM > Subject: RE: reverse mounting lenses > > > > Wireless flash and P-TTL are both useful but not essential. HSS, > > contrary to > > what you implied, is not a good idea for stopping a motion. > > > > At the speeds beyond the flash sync speed the shutter is never > > completely > > open, hence a single flash pulse cannot expose entire frame. HSS > > works by > > delivering a series of light pulses that are sync'ed with movement > > of the > > gap in the shutter that let's the light to the film/CCD. This means > > that > > the fast moving subject is "frozen" several times with several light > > pulses. > > HSS is only good for fill flash on a sunny day if you want to shoot > > open to > > reduce DOF. > > > > To freeze the motion you're much better off using shutter speeds > > lower than > > the sync speed. Remember, the duration of a single flash pulse is > > 1/2000th > > of a second or less, depending on how much light is necessary. If > > you stop > > down enough, the fast moving parts (wings?) of the subject will not > > get > > recorded on the film/CCD so you'll see no blur. > > > > See http://webs.lanset.com/rcochran/flash/hss.html for some examples > > and > > more technical details. > > > > Leon > > > >>-----Original Message----- > >>From: David Zaninovic [mailto:[EMAIL PROTECTED] > >>Sent: Wednesday, May 11, 2005 5:38 PM > >>To: [email protected] > >>Subject: Re: reverse mounting lenses > >> > >>> Pentax flashes can deliver TTL even with screw-mount lenses, > >>but don't > >>> have any hopes for P-TTL. > >> > >>I would like to have P-TTL because of the wireless high speed > >>flash option on my D. I will try to find some tubes that will > >>transfer electrical contacts. > >>It is much easier to shoot bugs handheld with flash set to > >>1/4000 speed and have a few tries to get the focus right. > >> > >> > > >
