Fuji S5 focus accuracy beyond 15-20 ft.

[joshua daniels]

I'm a professional shooting with an S2 and S5. I very much like these cameras

in most respects, and prefer them to the equivalent Nikons for image quality.

However, I'm finding that my S5 has a distant focus issue and wondered whether

other posters have experience the same problems.

 

Images shot under about 15-20 feet away are generally sharply focus (not quite

as crisp as I'd like, but still quite good, and lack of sharpness I don't

believe is focus-related). But beyond that distance, focus becomes progressive,

though subtly, less exact. At infinity, the subject is decidedly out of focus.

 

If you've experienced this symptom, please let me know--and what you've found

to be the solution.

 

Thanks!

[pete_s.]

I don't have a fuji but most modern dSLR works the same way.

 

Basically the image entering your lens is split three ways. One way is straight in to the sensor, one is reflected on a small mirror down the af sensors and one is reflected of the main mirror up into the viewfinder. If any of the components in the light path is slightly off you will have a problem. Some of it is mechanical adjustments but the autofocus sensors are calibrated with a computer.

 

You need to send in the camera to fuji or a service center and have them calibrate the focus on your camera. If some of your lenses are still not right after calibration you need to send them in too.

 

Peter

[pete_s.]

Auto focus accuracy also depends on the camera settings as well as the technique of the user. Some cameras like Canon for certain (don't know about Nikon or Fuji but I guess they have it too) have af sensors that are designed to give high accuracy with fast lenses (f/2.8 and faster) so maximum lens aperture also matters.

 

Peter

[ShunCheung]

The Fuji S5 is essentially a Nikon D200 with a Fuji Super CCD sensor and image-processing engines. The AF part should be identical between the S5 and D300, and the Nikon D80 also uses the same Multi-CAM 1000 AF module.

 

Compared to the Multi-CAM 3500 (D3, D300) and Multi-CAM 2000 (D2H, D2X and F6), the Multi-CAM 1000 is slower and has only one cross-type AF point. Therefore, it can have some problems indoors in dark conditions. But generally speaking, its AF should be accurate.

[Jerry_]

Could you please include what lens or lenses this happens with?

[joshua daniels]

I have tested the S5 with a 35/2 AF-D, 28/2 AI-S, 80-200/2.8 AF-S. The results are the same: with infinity focus (confirmed in the viewfinder by green AF light and AF lock-on), critical sharpness occurs somewhere around 15-30 feet with the wide lenses, and more like 100-150 feet with the 80-200. All test were conducted at relatively high shutter speeds with lens a few stops down.