Stop Using f-stops...... Reasoning??

Don't be surprised! Lenses aperture and camera shutter speed are not accurate even with today's electronic control everything. In this respect little has improved over the last 20 years or so.

I like them because they make sense. They correspond with reality - the laws of physics and all. And just to annoy you, I'll mention that I just pulled out my Sekonic meter and five different lenses. Everything looks to be within a third of a stop of the expected results, except for one older lens that I know to have a sticky iris ... that one habitually over exposes for that reason (but it's not a mystery, isn't getting away with breaking the laws of physics or confounding any math rules, or doing it just to upset me).

I like knowing, in my head, based on experience, what f/2.8 is going to look like, vs. f/5.6 under the same circumstances (here, I'm referring to DoF). I like knowing that opening up from f/4 to f/2.8 means I'm buying a drop from ISO 400 to ISO 200, or that I'll get the benefits of 1/250th instead of 1/125th.

What I really notice, lens-to-lens, are significant differences in contrast, saturation, and apparent color temp. These things can feel a lot like differences in exposure until you look more closely.

with a modern camera try this. point the camera at a scene that the light doesn't change. shoot a series of pictures of exactly the same EV but different aperture and shutter speed. i.e. f/8@1/125, f/5.6@1/250, etc... and you will see they have different exposures. The problem is not so much with the f/stop and t/stop. If you shoot with your lens wide open all the time and you shutter speed is accurate, most lenses the different between the t/stop and f/stop isn't much.

Cheers Matt, I knew they were after me...;-)

I have no problem with f-stops with regard to how they'll look regarding DoF etc, just the way they are used. Stop theory, ie one of the whole units of the clicky wheel on the top = one of the coloured numbers on that lens ring thingy= adjacent film boxes on the chemists shelf....etc

AFAIK, the whole units of both are of identical magnitude.

I wonder if the reason this is now an issue (for me and others!) is the amount of exposure latitude when comparing film and digital is easily measurable and noticeably different?

"shutter speed are not accurate even with today's electronic control everything" According to Nikon, the D4 takes care of this issue and will provide the ultimate in accuracy.

With a D4 shutter that precise and/or accurate, it's all down to a little lever pushing on a sprung-loaded peg then.... ;-)

With TTL operation, is the metering done (and finalised) at full aperture before shutting down for the actual exposure or is there real-time exposure correction? So in Aperture Priority say I choose f11 and let the machine decide the shutter speed, is the speed I see in the viewfinder the speed actually used or can that change mid exposure and which is recorded in EXIF?

f stops, shutter speeds and ASA/ISO have worked for me for over 50 years . You must be doing something wrong. You can have the best equipment, but if your technique is flawed, your results will be disappointing.

Sorry Mike, but I've seen nothing to support your hypothesis about f-stops being grossly wrong. I currently have about a dozen Nikkor lenses that I use regularly, from old Ai and Ai-S MF Nikkors to the latest AF-S G versions, as well as a fair smattering of everything in between and some 3rd party lenses. Yes, I can see some variation in colour rendering, especially between the Nikkors and the 3rd parties; but a variation between f-stops - NO, definitely not.

I'd estimate that I use fully manual mode about half of the time outside, and 100% of the time when I'm using studio strobes, so I think I'd have noticed if my lenses were acting differently from each other.
I did once have a Nikon series E lens that was awry in the aperture department. This was easily noticed because auto exposures got darker as the lens was stopped down. The retailer refused to do anything about it, saying it was within spec. so I took matters into my own hands and adjusted the lens myself. Problem sorted and I've never bought at that store again. I've also had the inevitable sticky iris, but again this has been a definite fault and not sample variation.

I may have been lucky, but if so my luck has held for several decades. I'd look to your camera body, camera metering or handheld meter before declaring all lens apertures useless. BTW, the recognised industry standard for aperture calibration is that the apertures should be accurate to 1/3rd of a stop. Anything outside of this and you should be within your rights to ask for a replacement lens or adjustment under warranty.

Perhaps you could post some samples of the sort of exposure variation you're getting? Taken under controlled lighting conditions and using manual exposure mode of course.

WRT shutter speeds: Modern electronically timed shutters are incredibly accurate compared to the mechanical monstrosities of the pre-1980s.

Robert, I gotta say, that's not very helpful. If you take a lightmeter reading, set the controls correctly and you get an badly overexposed picture, you'd NEVER doubt your equipment? It's ALWAYS your fault?

With regard to why using a camera on Manual, that, let's face it, is hardly 'technique', gives variable results points to mechanical problems, not human error.