[6BQ5]

I think the comparison between Fuji's and Pentax's big zooms came up before in another thread. The same video was referenced if I'm not mistaken.

I have both lenses. The Fuji lens is a bit chintzy compared to the Pentax lens. You could probably beat an ogre to death with the Pentax lens and not lose alignment of the optical elements inside. Yes, Fuji's teeny foot is a miss compared to the rock solid unit on the Pentax lens. I feel like the Pentax lens is sharper for the same field of view and depth of field, especially with the K-1's 36 MP sensor.

However, I don't think the Fuji lens is as bad as some would want you to think. Optically, it's a good lens but not a great lens.

One thing the Fuji lens has going for it is the AF-C capabilities when coupled with a body like the X-T3. I photograph my kid's soccer games in low speed continuous mode and my low speed setting is configured to 5 FPS. I stand behind the goal, off to one side. When my boys have the ball and approach the goals I hold down the shutter button. The shutter starts cycling and damn near every shot from midfield to the goal is in focus. Imagine a burst of 20 to 50 frames and 90+% of them are in focus! And, I'm zooming out as my boys are running toward the goal. 5% of the frames are missed because I didn't track my boys well enough, 2.5% of the frames are lost because someone was in front of my boys, and 2.5% of the frames are just the camera missing what would/should have been a good shot. So, as a system, the lens works pretty good! There is no way the K-1 with 150-450mm can come close to that ... and maybe Ricoh never really wanted it to.

I understand the AF-C performance was criticized in the video and I'm not sure what the reviewer did or did not do. My Fuji doesn't work like that.

The AF-C performance could be big compromise of the Fuji that drove the overall design. Maybe Fuji had to make smaller, lighter, thinner elements so they can focus quicker. Yeah, I'd give up a few lp/mm for that kind of performance. If your subject is pretty much at infinity and panning across then of course the Pentax system wins hands down if the frame rate suits you.

A more interesting comparison I'm working on is with recent Sony's 200 - 600mm G lens. That lens is huge and heavy. It even has it's own strap hooks! The copy I have feels very similar to the Pentax design. It has a huge foot and well damped controls. Someone at Sony must of looked at the Pentax lens and said, "Oooo! We need some of those in E-mount!"

Perhaps a more relevant comparison would be the Sony 100-400mm lens. It's closer to the 150-450 in zoom range.

[troenaas]

The impression that Fuji has great lenses has to come from somewhere, but it certainly does not come from actual testing... Just look a a reliable website like OpticalLimits (formerly Photozone) and you'll see how Fuji lenses compromise on all kinds of optical aberrations, as well as corner sharpness. From an optical designer standpoint (which I am) these lenses are designed similarly to fixed lenses compact superzooms of yore, with heavy-handed corrections required to bring out any kind of acceptable results.

Sony appears to be the same, honestly. It makes me appreciate Pentax lens design even more.

Another very good reason to stay with Pentax. :-)

[Belnan]

Imo, bif have never been as challenging as children playing or shooting team sports. Pentax is more than adequate for bif, less so for random bicycle riders.

[luftfluss]

The impression that Fuji has great lenses has to come from somewhere, but it certainly does not come from actual testing... Just look a a reliable website like OpticalLimits (formerly Photozone) and you'll see how Fuji lenses compromise on all kinds of optical aberrations, as well as corner sharpness. From an optical designer standpoint (which I am) these lenses are designed similarly to fixed lenses compact superzooms of yore, with heavy-handed corrections required to bring out any kind of acceptable results.

Some of the Fuji lenses are extremely sharp. For example, the kit 15-45 is slightly sharper edge-to-edge than the DA15 Ltd. This was from photos I took with the DA15 mounted on a K70, and the 15-45 mounted on the Fuji X-T20. The Fuji 15-45 also easily matches the DA21 Ltd. The budget Fuji 35/2 WR is a match in sharpness compared with the DA 35/2.8 Macro, except in the far corners. My test photos were developed in Capture One Pro with lens corrections set to off and sharpening also turned off.

Where the 15-45 and 35/2 fall down, though, compared with Pentax is in saturation, contrast and flare resistance. Neither Fuji is as good in those aspects as the older SMC coated lenses, let alone the HD versions. Heck, the DA 17-70 also outpaces the Fuji lenses.

Since it seems the majority of people consider sharpness to be the most important attribute of a lens, it's no wonder Fuji lenses are held in high regard. But in my very limited testing, I found my Pentax lenses to produce images that were both livelier and more "real" when processed similarly to the Fuji gear. That said, I have a lot more experience with Pentax stuff, and perhaps if I had more experience with Fuji my opinion would change.

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Last edited by luftfluss; 10-02-2019 at 11:15 PM.

[Rondec]

I think the comparison between Fuji's and Pentax's big zooms came up before in another thread. The same video was referenced if I'm not mistaken.

I have both lenses. The Fuji lens is a bit chintzy compared to the Pentax lens. You could probably beat an ogre to death with the Pentax lens and not lose alignment of the optical elements inside. Yes, Fuji's teeny foot is a miss compared to the rock solid unit on the Pentax lens. I feel like the Pentax lens is sharper for the same field of view and depth of field, especially with the K-1's 36 MP sensor.

However, I don't think the Fuji lens is as bad as some would want you to think. Optically, it's a good lens but not a great lens.

One thing the Fuji lens has going for it is the AF-C capabilities when coupled with a body like the X-T3. I photograph my kid's soccer games in low speed continuous mode and my low speed setting is configured to 5 FPS. I stand behind the goal, off to one side. When my boys have the ball and approach the goals I hold down the shutter button. The shutter starts cycling and damn near every shot from midfield to the goal is in focus. Imagine a burst of 20 to 50 frames and 90+% of them are in focus! And, I'm zooming out as my boys are running toward the goal. 5% of the frames are missed because I didn't track my boys well enough, 2.5% of the frames are lost because someone was in front of my boys, and 2.5% of the frames are just the camera missing what would/should have been a good shot. So, as a system, the lens works pretty good! There is no way the K-1 with 150-450mm can come close to that ... and maybe Ricoh never really wanted it to.

I understand the AF-C performance was criticized in the video and I'm not sure what the reviewer did or did not do. My Fuji doesn't work like that.

The AF-C performance could be big compromise of the Fuji that drove the overall design. Maybe Fuji had to make smaller, lighter, thinner elements so they can focus quicker. Yeah, I'd give up a few lp/mm for that kind of performance. If your subject is pretty much at infinity and panning across then of course the Pentax system wins hands down if the frame rate suits you.

A more interesting comparison I'm working on is with recent Sony's 200 - 600mm G lens. That lens is huge and heavy. It even has it's own strap hooks! The copy I have feels very similar to the Pentax design. It has a huge foot and well damped controls. Someone at Sony must of looked at the Pentax lens and said, "Oooo! We need some of those in E-mount!"

Perhaps a more relevant comparison would be the Sony 100-400mm lens. It's closer to the 150-450 in zoom range.

I would blame a lot of your focus issues on the camera bodies. Pentax has not been known for stellar tracking auto focus. That may change with coming cameras, but as of right now, even the K-1 II is average at tracking at best.

(Not sure how much better Fuji is but it is supposed to be better).

[normhead]

The shutter starts cycling and damn near every shot from midfield to the goal is in focus. Imagine a burst of 20 to 50 frames and 90+% of them are in focus!

I've done it before with running dogs, who run a lot faster than your kids, using my K-3. I seriously don't see this as an issue with K-3, which is the same sized sensor. I have no doubt you prefer the Fuji. But from my experience, you're seriously underselling your K-70.

[bdery]

Some of the Fuji lenses are extremely sharp. For example, the kit 15-45 is slightly sharper edge-to-edge than the DA15 Ltd. This was from photos I took with the DA15 mounted on a K70, and the 15-45 mounted on the Fuji X-T20. The Fuji 15-45 also easily matches the DA21 Ltd. The budget Fuji 35/2 WR is a match in sharpness compared with the DA 35/2.8 Macro, except in the far corners. My test photos were developed in Capture One Pro with lens corrections set to off and sharpening also turned off.

Where the 15-45 and 35/2 fall down, though, compared with Pentax is in saturation, contrast and flare resistance. Neither Fuji is as good in those aspects as the older SMC coated lenses, let alone the HD versions. Heck, the DA 17-70 also outpaces the Fuji lenses.

Since it seems the majority of people consider sharpness to be the most important attribute of a lens, it's no wonder Fuji lenses are held in high regard. But in my very limited testing, I found my Pentax lenses to produce images that were both livelier and more "real" when processed similarly to the Fuji gear. That said, I have a lot more experience with Pentax stuff, and perhaps if I had more experience with Fuji my opinion would change.

I confess that I have little first-hand experience with Fuji lenses. A friend recently made the switch from Nikon to Fuji and I tried his gear for a while.

On the other hand, I'm an optical designer and lens reviewer. I've taken a look at results from OpticalLimits, SLRgear, etc. When left uncorrected, the lenses are indeed sharp, but they are lacking regarding distortion, aberrations,etc.

[wed7]

Is the Pentax the clear winner here?

[6BQ5]

Is the Pentax the clear winner here?

I think it depends on your criteria for victory here.

For portability, telephoto reach, and AF-C tracking/performance the Fuji system wins.

For static subject photography, ultimate sharpness, and subject isolation the Pentax system wins.

I wish someone would combine the best of both into one lens and system. The Sony 200-600 is spectacularly sharp, like the Pentax, with the reach of the Fuji ... but it doesn’t always track as well as the Fuji in AF-C. I think here the deficiency is in the body, an A7R III. It comes close to being the perfect hybrid solution though. Maybe the A9 series would come closer to a Fuji X-T3.

Maybe Ricoh finally woke up with their upcoming APS flagship and will offer a worthy AF system. Maybe that new system will run the AF on the 150-450mm as if the lens was possessed by a demon!

[Kunzite]

For portability, telephoto reach, and AF-C tracking/performance the Fuji system wins.

How so?

[boriscleto]

How so?

I would be interested to know as well. Since Fuji uses Sony APS-C sensors with their own filter in place of the Bayer filter...

The longest prime is a 200mm F/2 that costs more than the DA 560 and the longest zoom is the 100-400.

I guess you could stack two 2x converters on the 200 and get a 800/8...

[6BQ5]

How so?

The Fuji with the 100-400mm lens on APS gives an effective FF equivalent reach of 600mm. Pentax's 150-450mm on FF doesn't reach as far.

But ... your skepticism shook me awake. I am always thinking of the K-1. On a APS body like the KP the 150-450mm lens gives more reach. So, I stand clarified and slightly corrected.

The Fuji X-T3 has a 26 MP sensor whereas Pentax APS bodies are at 24 MP. I don't know how much "zoom by cropping" from 26 MP to 24 MP will give you. Will it partially make up for the extra 50mm on the Pentax lens?

[Kunzite]

The Fuji with the 100-400mm lens on APS gives an effective FF equivalent reach of 600mm. Pentax's 150-450mm on FF doesn't reach as far.

But ... your skepticism shook me awake. I am always thinking of the K-1. On a APS body like the KP the 150-450mm lens gives more reach. So, I stand clarified and slightly corrected.

The Fuji X-T3 has a 26 MP sensor whereas Pentax APS bodies are at 24 MP. I don't know how much "zoom by cropping" from 26 MP to 24 MP will give you. Will it partially make up for the extra 50mm on the Pentax lens?

Yeah, I am considering Pentax K as a system and it's only fair to not give Fujifilm an advantage which doesn't actually exist - surely if reach is more important than image quality you'd also have the option of a Pentax APS-C.

The difference from 24 to 26 is insignificant. The K-1 in crop mode would be at a disadvantage though.

[6BQ5]

Alright, alright ... so I opened up an Excel spreadsheet and had to try calculating some numbers. It's all in good fun.

Please tell me if my thought process is right or wrong.

I listed the native resolutions of the sensors and a cropped resolution (factor of x1.5). I kept all focal lengths in FF equivalent just to keep it simple. A KP with its APS sensor and the 150-450mm lens gives a FF equivalent of 450mm * 1.5 = 675mm. A K-1 with its FF sensor and the same lens gives 450mm.

I understand APS is already considered cropped and I am cropping a cropped sensor ... sort of. If we're going to crop FF sensors down to APS by a factor of 1.5 in order to zoom in a bit then we'll crop APS sensors down to whatever they crop to so we can zoom by the same factor. That means where a K-1 goes from 36 MP FF to 16 MP APS the 24 MP APS sensor goes to 11 MP.

If we crop down to 11 MP on all sensors then something like the KP gives more reach than anyone because of the extra 50mm on the lens. The A7R III gets an edge where the 42MP sensor surges ahead.

I can't attach the Excel file so I'm attaching a screen shot of it.

[boriscleto]

The Fuji with the 100-400mm lens on APS gives an effective FF equivalent reach of 600mm. Pentax's 150-450mm on FF doesn't reach as far.

But ... your skepticism shook me awake. I am always thinking of the K-1. On a APS body like the KP the 150-450mm lens gives more reach. So, I stand clarified and slightly corrected.

The Fuji X-T3 has a 26 MP sensor whereas Pentax APS bodies are at 24 MP. I don't know how much "zoom by cropping" from 26 MP to 24 MP will give you. Will it partially make up for the extra 50mm on the Pentax lens?

Now you're comapring apples to oranges. Fuji doesn't have a FF.