Faster (f/2.8) Lenses on 5DII or Slower (f/4) lenses on 5DIII?

[chas1113]

I wonder if Canon (or some enterprising measurebator) has actually quantified the autofocus speed/accuracy benefit on the 5D Mark III with f/4 lenses compared to the 5D Mark II with f/2.8 lenses? Anyone know?

Practically everyone has attested to the vast improvements of the 61-point AF system versus the 9 points of the 5D II with the same f/2.8 lenses. But for many of us (non-pros, hobbyists, or just people who don't like the weight/expense of the 2.8 lenses) have built lens kits comprised of slower f/4 zooms and the like. I currently have a 5DII that I like very much, but (like most) yearn for the AF accuracy of the 5DIII. My quandary is, would you benefit more by upgrading to f/2.8 lenses and keeping the 5DII or keeping your f/4 lenses and upgrading to the 5DIII. Which combinations would yield better AF results?

 

[Loswr]

That sort of thing is pretty difficult to quantify but I'd bet that, in general, an f/4 lens on the 5DIII would deliver better AF performance than an f/2.8 lens on a 5DII.

 

[chas1113]

Thanks, Neuro. I figured you'd have a definitive answer....

 

[Loswr]

Well, thanks....but I'd hardly call my answer definitive. An educated guess, at best. But I do know that my 24-105/4L nailed focus more frequently and consistently on my 1D X than my 70-200/2.8L IS II on my 5DII.

 

[chas1113]

That's good to know. Thanks. And consistent with what I would hope/expect.

 

[agierke]

It also would depend greatly on what area of the auto focus system was being used and under what conditions. It's not such a cut and dry situation.

Use of center point only and recompose on the 5d2 using F4 and above would most likely yield acceptable results in most circumstances. Try that at F2.8 and wider and your results will plummet.

I wanted more creative freedom out of my auto focus system plus added reliability at wide open apertures. Couple that with my transition to the use of fast primes and the 5D2 just didn't cut it. The 5D3 was a necessity for me and something I had been pining for since I purchased the 5Dc upon its release.

As a pro I needed predictable and dependable results in some of the toughest conditions. I got by with the 5D2 for a while only because I couldn't afford a 1D series camera, but there were far too many times the gear couldn't perform reliably for the way I wanted to shoot. The 5D3 changed that and I can now shoot with much more confidence.

As a non pro, you may or may not find a benefit to the 5D3s focusing system. You may see a more immediate benefit to a 2.8 zoom. Heck, I work with some pros who still won't consider shooting wider than F5.6 and have no interest in the 5D3s AF system. In the end it's to each his own.

For my own experience though, the AF system on the 5D3 brought added functionality to ALL my lenses to the point that it was like having a whole new set of lenses. It was that much better than my 5D2.

 

[Mt Spokane Photography]

As long as you just use the center point, the 5D MK II focuses quickly even in low light. The f/4 lenses in general are not quite as good as the newer f/2.8 lenses, but they are still very good lenses.

I'd say that the 5D MK II is still a worthy camera, and I'd go for the top of the line lenses. However, if you want to use other than the center point, or need to track subjects as they move, then a 5D MK III is the one.

I bought the MK III, and like it, but I have not used the advanced tracking features as much as I should. I did use them in low light, and found tracking was possible most of the time.

 

[scottkinfw]

A 5DIII is a lot less expensive than upgrading your current lenses.

You can always sell your old lenses and update one at a time as $ is available.

Of course, it is a matter of your preference, and there are tradeoffs either way.

sek

 

[chas1113]

It also would depend greatly on what area of the auto focus system was being used and under what conditions. It's not such a cut and dry situation.

Use of center point only and recompose on the 5d2 using F4 and above would most likely yield acceptable results in most circumstances. Try that at F2.8 and wider and your results will plummet.

I wanted more creative freedom out of my auto focus system plus added reliability at wide open apertures. Couple that with my transition to the use of fast primes and the 5D2 just didn't cut it. The 5D3 was a necessity for me and something I had been pining for since I purchased the 5Dc upon its release.

As a pro I needed predictable and dependable results in some of the toughest conditions. I got by with the 5D2 for a while only because I couldn't afford a 1D series camera, but there were far too many times the gear couldn't perform reliably for the way I wanted to shoot. The 5D3 changed that and I can now shoot with much more confidence.

As a non pro, you may or may not find a benefit to the 5D3s focusing system. You may see a more immediate benefit to a 2.8 zoom. Heck, I work with some pros who still won't consider shooting wider than F5.6 and have no interest in the 5D3s AF system. In the end it's to each his own.

For my own experience though, the AF system on the 5D3 brought added functionality to ALL my lenses to the point that it was like having a whole new set of lenses. It was that much better than my 5D2.

Agierke: This is particularly helpful as I am mainly a focus/recompose type. I wonder if the f/4 cross points of the 5D Mark III would really help me as they are arranged away from the center point....hmmmm.

 

[chas1113]

As long as you just use the center point, the 5D MK II focuses quickly even in low light. The f/4 lenses in general are not quite as good as the newer f/2.8 lenses, but they are still very good lenses.

I'd say that the 5D MK II is still a worthy camera, and I'd go for the top of the line lenses. However, if you want to use other than the center point, or need to track subjects as they move, then a 5D MK III is the one.

I bought the MK III, and like it, but I have not used the advanced tracking features as much as I should. I did use them in low light, and found tracking was possible most of the time.

Mt Spokane Photography: You nailed it. For most of my shooting, the 5D center point with assist points is adequate most of the time. There are occasions when shooting my dog (who's fast!) that the keeper rate is abysmal even in AI Servo. It would be for the focus tracking ability of the 5DIII that I would consider upgrading.

 

[chas1113]

scottkinfw: That's what makes this a quandary, I guess. If I were a pro sports shooter or BIF exclusively, it'd be easy: bite the bullet and ante up for a 1DX and all 2.8 lenses. There is something to the center point focusing capabilities of the 5DII, however, as my 100 L nails focus at 2.8 much more reliably than my f/4 zooms. Decisions, decisions! I think I may follow your lead and upgrade to 2.8s in the near term with an eye on body upgrade as prices drop. Thanks all.

 

[chas1113]

From Agierke: "For my own experience though, the AF system on the 5D3 brought added functionality to ALL my lenses to the point that it was like having a whole new set of lenses. It was that much better than my 5D2."

This is REALLY the way I want to go. It's taken me a while to build my lens stable and I like it pretty much the way it is. If the body swap would breathe new life into them, that would be my preference.

 

[agierke]

From Agierke: "For my own experience though, the AF system on the 5D3 brought added functionality to ALL my lenses to the point that it was like having a whole new set of lenses. It was that much better than my 5D2."

This is REALLY the way I want to go. It's taken me a while to build my lens stable and I like it pretty much the way it is. If the body swap would breathe new life into them, that would be my preference.

i think you will find that it will. its a change in approach but once you get the hang of it its well worth it. moving forward after that you can be confident that you will be getting the most out of any new lens purchases whether they be 2.8 zooms or fast primes.

if you feel strongly that focus point freedom and reliability is what you personally need for growth then the 5D3 is for you. staying with the 5D2 and going with 2.8 zooms will likely exacerbate any focus issues you may already be experiencing with the focus and recompose technique.

 

[Dylan777]

The dual cross points on 5D III make huge diff.

 

[chas1113]

Great responses guys....you've all hit on the main sensor design differences through anecdotal experience....appreciate it. Great brain trust here. Looks like it's a body upgrade for me.

 

[sanj]

I find these auto focus speed measurements and discussions bit unnecessary as the cameras and lenses are fast enough in most rarely ever to miss a shot.

 

[mrsfotografie]

Heheheh don't discount the 5DMkII, it's still one hell of a camera. AF is overrated just like full auto or 'Program' exposure. 8)

Why? Servo tracking and AF speed are never as fast as good anticipation. If you know where your subject will be, and you focus accordingly, you will nail your subject where even the best AF misses! I'm more and more convinced of this as my technique improves and I become less and less reliant on AF.

AF is slower than pre-focusing because the AF system measures and refocuses. This is always slower than pre-focusing.

Still I must admit I usually prefer my 7D for animal and sports photography, because (besides reach/crop) well sometimes I'm a little lazy and then I prefer technology to sort things out for me. :

 

[Loswr]

Use of center point only and recompose on the 5d2 using F4 and above would most likely yield acceptable results in most circumstances. Try that at F2.8 and wider and your results will plummet.

Sorry, but this is absolute tosh. You clearly don't understand the concept of non-stop down lenses with aperture coupled metering, which have been widely used since the 1960's.

You apparently don't understand, or are ignoring, the reasons Why Focus-Recompose Sucks, to which agierke was alluding.

 

[agierke]

Quote from: paul13walnut5 on Today at 09:28:46 AM
Quote from: agierke on September 17, 2013, 10:10:54 PM
Use of center point only and recompose on the 5d2 using F4 and above would most likely yield acceptable results in most circumstances. Try that at F2.8 and wider and your results will plummet.


Sorry, but this is absolute tosh. You clearly don't understand the concept of non-stop down lenses with aperture coupled metering, which have been widely used since the 1960's.


You apparently don't understand, or are ignoring, the reasons Why Focus-Recompose Sucks, to which agierke was alluding.

Thank you neuro, that was exactly what I was talking about.

And Paul13Walnut5, I've come to expect better from you than to rush judgement and toss out degradations like that. I do understand very well what you detailed in your post. But that doesn't circumvent the simple physics of shallow depths of field and the problems one encounters with the focus and recompose technique. You can get away with focus and recompose at F4 on most focal lengths but wider apertures than that it becomes a tremendous problem.

 

[paul13walnut5]

You apparently don't understand, or are ignoring, the reasons Why Focus-Recompose Sucks, to which agierke was alluding.

You apparently don't understand, or are ignoring, the reasons Why Focus-Recompose Sucks, to which agierke was alluding.

Neither of you apparantly understand that the shooting aperture has nothing to do with the focus accuracy.

f4 might get everything reasonably sharp at 17mm on 135mm / leica / minature format DSLR's, but won't get you far anywhere else unless eveything in your scene is on the same focus plane.

The advice is useless, tosh. My biggest gripe is that somebody would actually read it and try it and miss out on important shots. Might as well have said get a lens with hyperfocal scales and shooting everything at f11. It's got about as much to do with how AF works. Jaysus.

Unless of course you meant that we should all buy lenses no faster than f4 so we can give our AF systems a chance for point and recompose. Or try just not using it

I stand by it lads.