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Which Fuji lenses are up to speed for the X-T1 ?


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With all the talk about the speed of the AF of the X-T1, has anyone tested which lenses are up to it?

I have the 35/1.4, on of the first and oldest lenses, so wonder if it's AF speed was determined by the camera it was mounted on, or the motor inside the lens. AF speed on this lens on the X-Pro1 is average. Not lightning fast nor molasses slow.

How about the 14mm f2.8?

The newer lenses like the 18-55, 23/1.4 and 56/1.2 from reports seem to be have fast AF to keep up to the X-T1... is this a case of if you want to get the best performance on the X-T1 you have to get one the newer lenses? did Fuji upgrade the AF mechanism in the newer/latest lenses?

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  • 2 years later...

My opinion, based on owning the 18, 35, 60 and 18-55 is this:

The first generation lenses (18,35,60) all appear to be external focusing (the lens telescopes in and out) and appear not to use a ring or linear motor. I think this limits their focusing speed, and also explains why the 18mm is fastest and the 60mm is slowest - it is determined by the amount of physical movement required to run through the range of focus distances.

Fuji then obviously learnt, and the 18-55 has a linear/ring type motor, and I think has 2 of them. It is also internal focusing - elements within the lens move to change focus distance - hence the amount of movement is much smaller. As a result it will focus more quickly than the first primes.

The 55-200mm appears to be a similar design, but reports suggest it is slower - probably because of it's slower aperture, and also the elements that need to move are larger.

On the more recent primes (14mm, 23mm, 56mm) I am confused since Fuji talk about "coreless" motors, but when you read their PR fluff on the lens pages, they are very non specific what this means. It appears to be a different technology to what they state is used in the zoom lenses, and a coreless motor is simply a traditional rotary motor without an iron core, which reduces inertia. I also thought they may have been internally focusing, but when I've asked some people like Rico, the answer has been that the lens does telescope during focus - hence external focusing. On the 14mm this may be a non issue, but on a 56mm f1.2 I am surprised if AF speed is important.

The 14mm appears to focus quickly since if you read all the tiny asterisks that mark the footnotes to the "world's fastest AF" claims, they use the 14mm - one assumed because it's DOF is large and it's focus throw is short.

Rico reports the 56mm lens focuses quickly, but that according to Fuji also only has a "coreless" motor, not a ring or linear motor as used in other brand premium lenses. Those type of motors have low inertia and high torque, hence are suited to fast movements and also the need to move heavy lens elements like those found in large aperture lenses.

I think what all this means is that Fuji have partly understood and responded to the early criticism of AF speed. A recent interview with Fuji also make reference to "refreshing" the lens range (make of that what you will). I think the initial primes AF speed will be limited by the design and technology used in them. The zooms less so. The other primes, somewhere in between.

I did ask one blogger here who has been reporting on the AF speed of the X-T1 if he had been using the early primes such as the 60mm, but I did not get a reply. The other unanswered question is whether the AF speed is maintained in all light - the X-E2 which shares much of the same electronics was reported to slow down considerably as light levels dropped, since the cameras must resort to CDAF and lens AF speed and quality of the Fuji AF software.

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Yesterday I made some informal AF tests: try to focus back and forth between a switched off lamp and a stack of books in very low light condition near my bed with: X100S, XE-1 + 18mm and XE-2 with 23mm. So, probably XE-2 with 23mm was using CDAF during the test. I was using AF-S with central AF frame for all of them.

The slowest one is XE-1 + 18mm, but not so slower than X100S. In both cases, the lenses were trying to go front and back movement until finding the focus. The quickest one is XE-2 with 23mm: I only slightly noticed the front and back movement with this kit. Even though XE-2 was using CDAF, I think it is a real improvement compared to XE-1 and X100S.

In lit conditions, X100S focuses quickly probably because of PDAF, but I think the CDAF algorithm in X100S probably is the same as XE-1.

Artuk, relative to 55-200mm zoom lens, I don´t think the focus is slow. It isn´t easy enough to focus for tracking sports and kids, but it is possible and the focus success rate in my opinion is good enough for personal/travel purposes (> 75%).

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Yesterday I made some informal AF tests: try to focus back and forth between a switched off lamp and a stack of books in very low light condition near my bed with: X100S, XE-1 + 18mm and XE-2 with 23mm. So, probably XE-2 with 23mm was using CDAF during the test. I was using AF-S with central AF frame for all of them.

The slowest one is XE-1 + 18mm, but not so slower than X100S. In both cases, the lenses were trying to go front and back movement until finding the focus. The quickest one is XE-2 with 23mm: I only slightly noticed the front and back movement with this kit. Even though XE-2 was using CDAF, I think it is a real improvement compared to XE-1 and X100S.

In lit conditions, X100S focuses quickly probably because of PDAF, but I think the CDAF algorithm in X100S probably is the same as XE-1.

Artuk, relative to 55-200mm zoom lens, I don´t think the focus is slow. It isn´t easy enough to focus for tracking sports and kids, but it is possible and the focus success rate in my opinion is good enough for personal/travel purposes (> 75%).

To qualify what I said, in good light for anything but sports or moving things, the AF speed is "good enough".

For moving things, particularly random movement, in good light, the AF is not so good.

My greatest frustration comes in low light or low contrast light. For example, a candid of a friend over dinner (not posed, so moving as they talk and eat) in low interior light seems beyond the ability of the X Pro - by the time it has managed to decide the focus distance, if it can at all, the subject has moved on. The other issue is that in low contrast conditions, even with AF assist turned on, with off centre subjects it just won't focus reliably.

The other issue is back lit subjects cause mis-focus, even in good light, and sometimes result in the inability to focus at all.

My experience on earlier versions of the firmware have blighted my opinion so much that I regard the 60mm and to some extent the 35mm as a lost cause when the light gets low and things might move. As a result, I am nervous about buying the newer primes, as they are far from cheap if I can't rely on them to focus efficiently in the same way an SLR can.

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One reviewer said until the X-T1, Fuji had been 'thinking out loud'. That is reflected in AF speed more than anywhere. It's all relative of course, unless you shoot sports, close up street photography or hyper-active kids, you may not miss quick autofocus.

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The DPReview Fujifilm interview gave me the impression that Fujifilm intends to revise and reissue the original prime lenses with improvements. A bummer for us early adopters, but definitely a necessity.

http://www.dpreview.com/articles/5988185050/fujifilm-interview-the-only-way-is-to-keep-innovating

The X-series is maturing now - what lessons have you learned along the way?

Since we launched the X-series with the X100 we created a lot of cameras, and even since the X-Pro 1 was launched we made the X-E1, X-E2, X100S, X-M1, X-A1 and X-T1. I think we did too much too fast, and made too many models. Some customers have told us that it’s confusing. So now we will slow down, step back and look at what our customers are buying, and what they want.
We also need to refresh our lens lineup.

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One reviewer said until the X-T1, Fuji had been 'thinking out loud'. That is reflected in AF speed more than anywhere. It's all relative of course, unless you shoot sports, close up street photography or hyper-active kids, you may not miss quick autofocus.

I would like to believe that it is true - but firstly they have been prone to pr fluff about worlds fastest AF, secondly the sensor and hardware are mostly the same as the X-E2, and lastly "worlds fastest" in ideal conditions with Fuji may be something much less impressive in less than ideal conditions. I am hoping to good take a good look at one at the UKs "Photography Show" next month.

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Thanks Artuk.

Sounds like my 35/1.4 should stay on my X-Pro1 and maybe my 14/2.8 might just be a half-decent match for the X-T1 - if I get one that is. Might hold out for the X-Pro2.

Of all the Fuji lenses, which one is best suited with the X-T1 for fast moving kids? The 18-55?

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Using zone focus—any lens. There is no need to focus on the subject, so long as the subject is in the zone of focus. Realize that most sports are way quicker than any kid, and great sports photography was done on low-ISO film with purely manual cameras. No auto-focus at all. All Nikon's pro-sports super-telephoto lenses have a thumb-switch to instantly kill autofocus as needed. It is a technique that is simple to learn and works 100% of the time.

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Using zone focus—any lens. There is no need to focus on the subject, so long as the subject is in the zone of focus. Realize that most sports are way quicker than any kid, and great sports photography was done on low-ISO film with purely manual cameras. No auto-focus at all. All Nikon's pro-sports super-telephoto lenses have a thumb-switch to instantly kill autofocus as needed. It is a technique that is simple to learn and works 100% of the time.

That's a great idea when stopped down - but is not suitable for large aperture work (typically required in low light, when the AF is at it's worst). If I zone focused my friend over dinner, I would need an ISO that was beyond any available in a Fuji camera.

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Thanks Artuk.

Sounds like my 35/1.4 should stay on my X-Pro1 and maybe my 14/2.8 might just be a half-decent match for the X-T1 - if I get one that is. Might hold out for the X-Pro2.

Of all the Fuji lenses, which one is best suited with the X-T1 for fast moving kids? The 18-55?

Of the lenses I own (18,35,60,18-55) the zoom is the fastest focusing. Rico talked about the 56mm focusing quickly on the new camera, and Fuji make their "worlds fastest" claim using the 14mm.

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Yeah, I thought the 18-55 would be the fastest out of your lineup.

The Fuji statement that the "worlds fastest" is attributed to the 14mm is interesting. I'll have to try it out. Probably as you've said b/c of it's large DOF and it's focus throw is short. Really, you would think that would make this claim with a more standard or moderate wide like the 23mm...

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Yeah, I thought the 18-55 would be the fastest out of your lineup.

The Fuji statement that the "worlds fastest" is attributed to the 14mm is interesting. I'll have to try it out. Probably as you've said b/c of it's large DOF and it's focus throw is short. Really, you would think that would make this claim with a more standard or moderate wide like the 23mm...

I'd love to see a figure quoted with one of the initial primes, such as the 35mm f1.4, as that's a "standard" lens for the system that clearly didn't have it's design thought through when it came to focus speed. It amazes me that Fuji have to constantly go through a "learning" process when almost everyone else in the industry already has an answer.

It's notable that most bloggers who have been given X-T1s to try and write about seem to be using zooms or newer primes - I have seen none that talk about using the 35mm or 60mm, for example. I am sure it is deliberate on Fuji's part.

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And probably a silent release of the 35/1.4 VII with updated AF mech.. or you'll hear it marketed loud and clear.. the Fuji PR machine is well oiled in this respect..

If the quote from the Fuji representative is true, and not a misunderstanding about "refreshing the lens line-up" (my words), then I am somewhat surprised. It's rare for a company to replace standard primes on a 2-3 year cycle, it's more typically decades. Some might see this as an example of Fuji's responsiveness to customers etc, but I would interpret it as an admission that they got "something" wrong with some lenses if they needed to replace them with new models so quickly. However, given that the reports of lenses like the 23mm and 56mm are capable of fast focusing, it seems something has changed. I do get a tremendous sense that Fuji has gone through a period of significant learning in the last couple of years (with early users their lab rats!).

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Some might see this as an example of Fuji's responsiveness to customers etc, but I would interpret it as an admission that they got "something" wrong with some lenses if they needed to replace them with new models so quickly. However, given that the reports of lenses like the 23mm and 56mm are capable of fast focusing, it seems something has changed. I do get a tremendous sense that Fuji has gone through a period of significant learning in the last couple of years (with early users their lab rats!).

Absolutely agree. There's a lot of talk about Fuji's responsive attitude to customers and their firmware updates, some of it well deserved, but most of the updates were to fix basic functions to the level of their competitors.

It seems like the latest iterations are the first to really perform without some kind of compromise.

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Some might see this as an example of Fuji's responsiveness to customers etc, but I would interpret it as an admission that they got "something" wrong with some lenses if they needed to replace them with new models so quickly. However, given that the reports of lenses like the 23mm and 56mm are capable of fast focusing, it seems something has changed. I do get a tremendous sense that Fuji has gone through a period of significant learning in the last couple of years (with early users their lab rats!).

Absolutely agree. There's a lot of talk about Fuji's responsive attitude to customers and their firmware updates, some of it well deserved, but most of the updates were to fix basic functions to the level of their competitors.

It seems like the latest iterations are the first to really perform without some kind of compromise.

+1

I know it does not make me popular around Fuji parts when I make disparaging comments about my X Pro 1 - but I feel where the cameras are getting to now is where the X Pro should have been 2 years ago, when it was released at the same price as a 6D or D600.

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From Expert Review, on the X-T1 focusing:

"Phase detection also helps with autofocus performance. We measured times of between 0.3 and 0.7 seconds to focus and capture a shot, with 0.4 seconds being typical. Shot-to-shot performance in normal use came in at 0.7 seconds. These are solid results, but not outstanding. Continuous mode was far more impressive, delivering speeds up to 6.3fps with tracking autofocus. This lasted for 40 JPEGs or 20 RAW frames before slowing to the speed of the card. Continuous shooting with fixed focus was even faster, at 8.3fps. This level of performance compares well with the fastest SLRs at this price. However, it's a little disappointing that the X-T1 can't track subjects as they move around the frame – a feature that's fairly common among compact system cameras. Face detection is available, but enabling it overrides any other autofocus settings."

They made no reference to the lens used, but almost certainly the standard zoom which forms part of the "kit".

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  • 3 weeks later...

Pom it's not your lens it's the body, the 35 will be much faster in a newer body with phase detection and faster CPU....

Does Pom have a X-E1 or X-E2? The X-E2 has the same sensor and processor as the X-T1, I believe.

The focusing performance of the X system does appear to vary by model. My opinion, based on the lens design, is that the original 3 primes are likely to be the "slowest", as subsequent lenses have different focusing designs (I assume to improve AF speed).

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