[thxbb12]

Strange, even my EOS 450D gives me reliable, accurate PD AF. The newer Canon models are even better (5D mk III, 60D, 650/700D, 1D X, 6D). I even get accurate focus with MF lenses relying on focus confirmation with PD AF (Nikkor-H 80mm f1.8, Nikkor Auto 55mm f3.5 micro, Ultra Micro Nikkor 55mm f2). Even my Sigma 18-50mm f2.8 EX DC, which was a total disaster on the 350D concerning AF accuracy behaves pretty well on my 450D.

 

The D800 seems to be a step back from the D700 and D3(S), a while back I have read (in some dpreview forum thread) that it does things with points around the AF point you are thinking you use, which causes surprising AF results at times. And this causes frustration with users. 

 

Try a different DSLR to notice the difference.

 

The D800 is my first Nikon camera so I can't tell whether it's better or worse than a D3/D700. The thing is because of the high pixel density and the fact we can check results at 100%, focusing errors, even very small will be more noticeable on a D800 than on a 12MP camera. Additionally, unless  you print quite big, it's unlikely that on a D800 any small AF error will be visible.

I used to have a K5 and the issue was actually much worse (AF was the main reason why I left Pentax actually).

 

The mere fact of the existence of micro-adjustments clearly shows the issue is very real. This is the (dirty) fix manufacturers have found in order to allow users to correct for AF calibration issues.

 

Of course, focus issue is lens dependent and once a lens is calibrated (I use FoCal which is pretty good to semi-automate the process), it gives great accuracy. However, despite this, focus is not always reliable and consistent which forces me to usually take several identical shots "just in case". Moreover, FoCal recommends users to recalibrate their lenses once a year, because of AF drift over time.  When it comes to AF calibration, fast zoom lenses are a real pain: take a 70-200 f/2.8 lens for instance. Chances are that you'll need say -5 AF adjustment at 70mm and +4 at 200mm.  What do you do then? You have to bias the AF towards the focal length you use the most or choose something in between where the center of the range will be spot on while the short and long ends won't be perfect.  That's just great!

 

Working on the final image is really the strongest point of mirrorless. It doesn't matter if the focus sensor is not perfectly aligned since you work on the final image.  You don't need to review your shots as you know they'll be in perfect focus.  Camera/lens calibration is a thing of the past.  It's just so much better and enjoyable to use.

 

Maybe I'm particularly picky, I don't know. I'm just starting to be really fed up with this whole PDAF crap.

[nandadevieast]

BrightColors,

 

I am only saying from my personal experience.

I have shot with Canon DSLRs also...including 450D, 5DMII...

Nobody is saying that they don't work. Otherwise people won't use them. 

All i'm saying is, there's a agreed and well-understood way of working with a DSLR..."get many shots"...

Its a bit frustrating when there's a alternative system around and you can see that focussing is so much more accurate without this trial and error/chimping involved. 

I also tend to think that the continuous tracking abilities of DSLRs are over-rated. 

[Brightcolours]

BrightColors,

 

I am only saying from my personal experience.

I have shot with Canon DSLRs also...including 450D, 5DMII...

Nobody is saying that they don't work. Otherwise people won't use them. 

All i'm saying is, there's a agreed and well-understood way of working with a DSLR..."get many shots"...

Agreed? I find it rather debatable. I never have to do that "get many shots". These images were without AF, but with AF confirmation and/or trap focus using the PD AF sensor, with just one try:



I might make more photos of a subject, but that then is to try to catch the best angle or composition... The above shots were with my 55mm f2, but I get similar results with my 85mm f1.8 and 55mm f3.5 with focus confirmation using PD AF on my low-end EOS 450D.

 

Also with PD AF I get fine results without having to shoot many same shots (again, I shoot most compositions once when using focus confirmation or AF):

Anemones with 35mm f2

Horses with crappy Sogma 18-50mm f2.8 EX DC

Windmill with 70-200mm f4 at 200mm.

Its a bit frustrating when there's a alternative system around and you can see that focussing is so much more accurate without this trial and error/chimping involved. 

I don't have that trial and error problem much, really (I did when I had the Canon EOS 350D). If you do, something is wrong with your equipment, either calibration wise or design wise. As I pointed out above, apparently something is going on with the D800 AF, which makes it to some rather temperamental? Maybe something to research.

I have to point out (for completeness) that above 3 lenses never were sent in for calibration, nor has my 450D ever seen any service. I do however have a Tamron 90mm f2.8 which focusses like shit at infinity (ok-ish at close up distances). I have used a Canon EF 100mm f2.8 USM macro which focussed rather inaccurately on an EOS 50D, but focussed spot on on my 450D.

I also tend to think that the continuous tracking abilities of DSLRs are over-rated. 

Overrated? If your shooting style does not need AF tracking much (mine does not either), it is a feature that is not important to you. But the AF tracking ability of PD AF is hardly overrated....

 

Can you show any examples of the AF goofing up so that you have to shoot and shoot in the hope that you get an in focus image? And is that in certain situations, or all the time? Can it have to do with the complex AF of your D800 not being set right for the type of shooting? Or is it linked to a particular lens?

[popo]

You may have gathered from my previous posts I do value tracking AF. And for sure it is far from perfect, particularly if you're using multi-points where it can easily get confused as to what exactly it is tracking.

I would agree that even single shot phase isn't perfect, but it is only really noticeable with fast lenses, say <f/2 <100mm, or f/2.8 longer than that. The AF point size is still rather big so it may pick on things other than what you thought.

However, contrast AF isn't perfect for the same reason. If the detection area is big relative to the target, you still run into problems. Arguably it may have a bit more consistency over phase though.

At the end of the day, I go with the thought "use the right tool for the job". Obviously that isn't limited to AF, but a whole bunch of features. Go with whatver works in a given role.

Right now for me, phase will give me a higher hit count than single shot. Looking into the future, if they can combine the best of both phase and contrast AF into a single system, you can bet I will jump on it. Existing hybrid systems still have some way to go to get there.

[borisbg]

This is so true.

 

I own a D800 and a Pana G3.  I'm more and more thinking about dropping the D800 to go full MFT instead (when Olympus will finally decide to release a body with integrated EVF, 100 ISO, small focus points and 1/8000 shutter speed).

PDAF is just not reliable, no matter what people say. I can't care less about focus tracking.  I just want reliable single AF shots. Nothing less, nothing more. Yet, only CDAF delivers true reliability.  I love my G3 for this as I don't have to constantly reivew my shots to make sure they are in focus.  Plus, the focus calibration is just a nightmare.  I'm so tired of this "archaic" tech.

 

What I'd really like to see is MFT with a FF sensor

Leica is just "click" away.

[mst]

Leica is just "click" away.

But AF is miles away then

-- Markus

[Brightcolours]

The D800 is my first Nikon camera so I can't tell whether it's better or worse than a D3/D700. The thing is because of the high pixel density and the fact we can check results at 100%, focusing errors, even very small will be more noticeable on a D800 than on a 12MP camera. Additionally, unless  you print quite big, it's unlikely that on a D800 any small AF error will be visible.

True, but one should also not overstate the pixel density of the D800. It has the same pixel density of a 16mp 1.5x crop sensor, and is not far from the pixel density of my 12mp 1.6x crop camera.

I used to have a K5 and the issue was actually much worse (AF was the main reason why I left Pentax actually).

 

The mere fact of the existence of micro-adjustments clearly shows the issue is very real. This is the (dirty) fix manufacturers have found in order to allow users to correct for AF calibration issues.

True, but not all cameras show the same AF calibration issues. When the EOS 60D was announced many were angry that Canon dropped the MFA from the 50D... But practice has shown that that model does fine without MFA.

The Canon 5D mkIII and 1D-X seem to be ahead of the game AF accuracy wise.

Of course, focus issue is lens dependent and once a lens is calibrated (I use FoCal which is pretty good to semi-automate the process), it gives great accuracy. However, despite this, focus is not always reliable and consistent which forces me to usually take several identical shots "just in case". Moreover, FoCal recommends users to recalibrate their lenses once a year, because of AF drift over time.  When it comes to AF calibration, fast zoom lenses are a real pain: take a 70-200 f/2.8 lens for instance. Chances are that you'll need say -5 AF adjustment at 70mm and +4 at 200mm.  What do you do then? You have to bias the AF towards the focal length you use the most or choose something in between where the center of the range will be spot on while the short and long ends won't be perfect.  That's just great!

Nothing beats a well calibrated lens, indeed MFA is not a cure or substitute. Most lenses which are not accurate show differences at different focus distances too.

Working on the final image is really the strongest point of mirrorless. It doesn't matter if the focus sensor is not perfectly aligned since you work on the final image.  You don't need to review your shots as you know they'll be in perfect focus.  Camera/lens calibration is a thing of the past.  It's just so much better and enjoyable to use.

 

Maybe I'm particularly picky, I don't know. I'm just starting to be really fed up with this whole PDAF crap.

Try a 5D mkIII in a store one time, you might be surprised?

[thxbb12]

True, but one should also not overstate the pixel density of the D800. It has the same pixel density of a 16mp 1.5x crop sensor, and is not far from the pixel density of my 12mp 1.6x crop camera.

 

My answer was in reply to the comment about D3/D700 not showing any AF inaccuracy. Their density is much lower than a D800.  My previous DSLR was a Pentax K5 which indeed has the same (roughly) density as the D800. Note that my K5 had much more AF reliability issues than my D800.

 

 

True, but not all cameras show the same AF calibration issues. When the EOS 60D was announced many were angry that Canon dropped the MFA from the 50D... But practice has shown that that model does fine without MFA.

The Canon 5D mkIII and 1D-X seem to be ahead of the game AF accuracy wise.

Nothing beats a well calibrated lens, indeed MFA is not a cure or substitute.

 

 

What does MFA stand for, manual Focus Accuracy?

I'm not interested in manual focusing, whether with an aid in the VF or not. The only times I might need manual focus is with macro work which is a very specific case where AF is usually not an option anyway.

 

Most lenses which are not accurate show differences at different focus distances too.

 

True. Which is one more annoyance to add to the list against PDAF (versus CDAF). My Tamron 90 is notorious for this.

 

Try a 5D mkIII in a store one time, you might be surprised?

 

Perhaps, but I never considered Canon and won't now. In the past I found their auto ISO implementation extremely primitive and useless (compared to Pentax at least). Plus, I really disliked their ergonomics compared to Pentax.

In more recent year, I've found them to be quite sub-par in terms of sensor technology, especially DR.  Their sensors have marginally improved in the last 7 years. Back in 2005 they were clearly ahead of the game. Nowadays it's rather the opposite.

 

Anyway, I think DSLR tech is outdated and it's just a matter of time until mirrorless completely takes over. It may take a few years, but it's gonna happen for sure.

I wonder which manufacturer will come up with the first FF mirrorless interchangeable lens camera. Samsung? Sony? ...

[Brightcolours]

My answer was in reply to the comment about D3/D700 not showing any AF inaccuracy. Their density is much lower than a D800.  My previous DSLR was a Pentax K5 which indeed has the same (roughly) density as the D800. Note that my K5 had much more AF reliability issues than my D800.

 

 

 

 

What does MFA stand for, manual Focus Accuracy?

Micro Focus Adjustment?

[thxbb12]

Micro Focus Adjustment?

 

Ah thanks, it makes much more sense - for some reason I didn't even think of it (!).

Agreed, MFA is not a substitute to the real issue, but it's still the best way to fix it besides sending the camera + lenses back to the manufacturer. Even if they calibrate it properly, chances are that a new lens might require a focus adjust as well.

On my previous bodies, I noticed that AF accuracy tends to change over time (with certain lenses at least).  I would personaly never consider buying a DSLR lacking micro AF adjustments.

 

Btw, instead of:

"I wonder which manufacturer will come up with the first FF mirrorless interchangeable sensor"

 

I meant to write:

"I wonder which manufacturer will come up with the first FF mirrorless interchangeable lens camera"