To me, from reading every review, and discussion, and owner comments, it is clear that these 2 cameras are at the head of the class, for AF speed in general, and low light AF speed, specifically. The F828 is right up there too, but at the price difference for the V3, I don't see the advantages.
I couldn't decide which to get, or if either was really good enough, so I gave up, and got both together for awhile, so I can compare them for things that matter to me, before returning one of them, and eating the restock fee.
My perspective is as an underwater photographer, where light/contrast tends to be low, and where you always shoot with fill flash, to bring back the colors, or pure flash only exposures at night.
I shoot my cameras A mode, if it works well enough, otherwise Manual. I like to control the aperture first, for DOF and strobe power limits.
Underwater, you also almost always shoot in the 6 inch to 3 or maybe 4 foot distance range, so the water doesn't absorb the reds from the strobe, and gunk in the water does not drop the contrast of the subject, too much.
The Pro1 is available for $600 or less now, and the V3 is right about $500.
The Pro1 has lots of flash adjustments, over +/- 2 stops, while the V3 has high, normal, and low.
The Pro1 feels very heavy in the hand, for its size. The V3 almost feels too light. Both seem very solid.
The 28-200 zoom range of the Pro1 is nice, but 28mm is not really wide enough. I'd rather have a 5x zoom that started at 20 or 24... The problem here, is there is no way to add a WA lens on the Pro1, as can be done with the V3 or G6.
Image quality:
Both are good enough, at their lowest ISO settings. With the same shots, in the same lighting, the color balance is remarkably similar. I'm calling it a wash.
Since I am used to shooting ISO 50 slide film for so many years, the digi's low ISO does not bother me at all.
LCD:
Both are fine in daylight.
Both have some noticeable lag in them. Hard to say how much. These need to be running closer to video rates!
Both have big advantages over SLRs, in terms of composing your shot when it is too dark to see anything in an SLR's viewfinder. As long as flash is on, or they think an external flash is attached, they raise the gain, to make the LCD display useful, even in very dark conditions.
The twist, turn, and swivel LCD on the Pro1 is nice, occasionally.
Zoom and macro/normal focus ranges:
The Pro1 zoom ring, while nothing near a manual zoom ring, at least beats the V3's toggle. The Pro1 allows nice small smooth movements. The V3 is jumpy. Trying to zoom small amounts is problematic. It zooms from .2-.3 X per smallest possible button push. If you are trying to make small adjustments, it is hit or miss - go past, and come back...
The V3, in macro focus mode, still focuses clear out to infinity. And it has a nice smooth gradual moving out of the closest focus distance, as you zoom in. Macro mode works across the entire zoom range.
This is killer for uw-photo, as you can just leave it in macro mode all the time.
The V3 gives slightly greater maximum image magnification, than the Pro1, and gives it at a better working distance.
The Pro1 macro mode is very choppy across the zoom range, and hard to find the sweet spots for maximum magnification. It allows very close focus, from wide - 63mm, then it jumps out from there to 90. Past 90 there is no macro focus.
The Pro1 macro mode only focuses from 4 inches to about 2 feet at the wide end, and 1 foot to 1.6 feet, at the 63-90 end. If your subjects are often in the 1-3 foot range, this will entail lots of switching in and out of macro mode.
One mitigating feature, is the Pro1's user defined setups, which allow you to preset all shooting modes, including macro on/off, and preset the zoom position and focus range. This lets me save a setup for maximum macro mag, (at 63mm), and so on.
The Pro1 supermacro mode is cool, but the working range is even shorter, and it will not shoot RAW or full rez...
Final Half-Press Shutter Lag:
The V3 claims a final half press shutter lag of .014 seconds. However, like the V1, and all the F series, there is extra lag here, when using flash. And not only when using TTL flash, (where one might understand extra lag for measurements and calculations), but even when set to use an external non-dedicated dumb manual flash, in M, A, or S mode. The extra lag does not exist in P mode, which leads one to believe it is a sick attempt to sell sony dedicated flashes, which is the only way you could shoot P mode, with an external flash. Reported elsewhere, the extra lag on the V1 was .17 seconds, and on the F828 was about .25!
Best I can measure, the V3 inserts an extra about .1 seconds to the final shutter lag introduced, when using M, or A mode, and external dumb flash. This is NOT present in P mode, so it is the same firmware issue. So final shutter lag time is more like .114, rather than the advertised .014. So, in use with flash, it is slower than the Pro1's .077, though still faster than most SLRs...
Still, total full press shot times for the V3 are frequently in the .7 second range, and closer to .9-1.0 for the Pro1.
Autofocus:
In good strong daylight, my film SLR focuses on a contrasty spot in about .1-.2 seconds, and when the focus is already close, it is much faster.
In that same light, the V3 focuses in about .3 seconds, in the wide half of the zoom, and maybe .5 -.6 seconds at tele. It does not speed up much, if the focus is already very close.
The Pro1, (yes it has updated firmware), focuses about .6 seconds across the low half of the zoom range, and maybe slows down to .8 or .9 at extreme tele. It does a bit better than the V3, at being faster, when the focus is already near, and occasionally will give a very quick lock.
In bright indoor light, (say as bright as a well lit kitchen with overhead fluorescent bulbs iso100 - f2.8 1/20), or brighter, the V3 focuses noticeably quicker than the Pro1. Especially in the wider half of the zoom range, where it is a good .5 second faster total shutter release time.
But as the light dims down below that, the Pro1 focus time seems to maintain better than the V3. In the dimmest light in which they will give focus lock, without their assists, the Pro1 still focuses in about 1 second, while the V3 can take as long as 2 seconds. Indeed, if you just fully press the shutters, that is how long the lags will be, very reliably. And with both cameras, 9/10 or more will be in focus.
When it is darker than a certain point, the V3 switches over to hologram AF, and takes nearly 2 seconds for a full press shot. It does get the focus right, all the way down to pitch dark.
The Pro1 also focuses correctly, down to pitch dark, at least in the wide end. This uses the ranging sensor, and take about 1 second.
If you block the ranging sensor, (as it would be in an underwater housing), it still focuses in remarkably dark conditions, and does not seem to slow it down much if any.
Even without their focus assists, (hologram on V3 or range sensor on Pro1), these cameras will focus clear down to where it is too dark to use an SLR, and where my n90s with a 2.8 lens will not focus! But they are sssslllooowwww at that point.
Manual focus:
The V3 is horrible here. Called "focus presets". They go back to what it was the last time you left manual focus mode. So, there is no interaction between what the autofocus just did, and MF.
The Pro1 has this right! MF just freezes the distance where it is right now, and you can adjust from there. Can also be used as a "focus lock", to focus, lock, recompose...
Exposure modes:
In the V3's M mode, you can still choose auto or manual flash. Pro1 M mode allows manual flash only.
I wish all camera manufacturers would put in a user adjustable lowest shutter speed for A mode. For some subjects, 1/60 is too slow, leading to motion blur, for others 1/40 or 1/30 would be fine...
RAW mode:
Pro1 is great. Fast cycle times, in RAW. A joy to use.
V3's RAW totally locks up the camera, dead as a rock, for 12+ seconds. Unusable in RAW.
Small issues and nit pickings:
With the Pro1, every time you go to manual focus and back, it forgets that you had macro focus mode on. In fact, every time you change exposure modes, or turn the cam off and on, it forgets it. The custom settings allows you to force the macro mode on, when you turn to that setting, or turn the camera on in that setting. But this isn't as good as leaving the macro focus mode alone!
When you take a shot with the Pro1, and have review on, you can jump out of review by pressing the shutter. Several times I found myself trying to zoom, for the next shot, but the zoom is dead during review. This should be given priority, like the shutter. Or it should be a real manual zoom.
With the V3, if you are shooting in dim light, with settings that will underexpose by a whole lot, and turn off the flash, it stops brightening up the LCD, which goes nearly dark, as does the Pro1, but with the V3 this actually makes it fail to focus, even though in should "know" it can gain up for focus. The Pro1 does exactly that.
For underwater, anything over 100 mm equiv focal length, is good only for macro. (Shooting through 6 or more feet of water almost always ends up in hazed out, low contrast pictures of shades of blue.) Alas, the Pro1's macro focus setting only works from wide-90mm focal lengths, so underwater, half the lens is wasted.
Conclusion:
Both cameras need faster LCD update rates.
The Pro1 needs faster AF performance, and more useable close focus modes.
If you need RAW, the V3 is out.
I hope the next generation of each of these, will solve some of the issues.
