Meike 2.8/28 Fuji-X : image quality, design, customer service

[bernard_L]

Bought last spring a Meike 2.8/28 manual focus for my Fuji XE-2. Image quality is good (see below full image, and 100% scale crop). That is the good news.

The not-so-good news.

• The aperture scale is... strange. See picture. Could it be that something is missing?
• The DOF scale is also strange. The f/5.6 mark is about twice as far from center as f/2.8as it should. But, the f/22 mark is just 50% further out than f/5.6, when it should be 4x farther.

And the bad news.

• When focused at infinity using the focus assist of the XE-2, the distance scale is half-way between infinity and 2m, i.e. where the 4m would be if present. Well, I should not complain, what if there was the opposte error and I could not reach infinity?? Last resort:
  https://scalefocus.wordpress.com/20...s-no-special-equipment-or-expertise-required/
  
• The face ring (with lens name etc) is also the filter attachment thread. First time I screwed/unscrewed a filter, the face ring rotated; following that the focus ring rotation is restricted, and infinity (scale or real) cannot be reached until the original position of the face ring is restored. Which will not last, because it moves freely.

On 17-Oct-2020 I submitted a request for service under warranty using the online form at
http://www.meikestore.com/ -- Customer service -- Contact us
"we will reply your enquiry in 1 business day"
On 02-Nov-2020 I sent a reminder by email to service@meikestore.com
Today is 15-Nov-2020...
I'll post updates if/when I receive a response from Meike.

 

[shutterfinger]

The face ring (with lens name etc) is also the filter attachment thread. First time I screwed/unscrewed a filter, the face ring rotated; following that the focus ring rotation is restricted, and infinity (scale or real) cannot be reached until the original position of the face ring is restored. Which will not last, because it moves freely.

The trim ring should be sealed with a thread locker from the factory. You can use a rubber stopper hollowed out to turn the ring, unscrew, apply clear nail polish, purple thread locker or blue thread locker about the size of a straight pin head to the threads where the ring is when fully tightened then install and fully tighten the ring and allow the thread locker to cure.

Aperture is the function of the entrance pupil to the lens focal length. The entrance pupil is the diameter of the aperture opening as viewed through the front of the lens. Lens focal length, measured not printed nominal, divided by the entrance pupil.

 

[bernard_L]

@ shutterfinger : Thank you for the suggestion; indeed thread locker (loctite 222) is what I'll use if it turns out I have to perform service myself. Trouble is, the face ring will not unscrew by more than 1/2 turn. I don't have the same approach on a new lens under warranty (at least in principle) as with a garage sale find.
I know the definition of entrance pupil, f-number, etc. I contributed to design, align, test, several astronomical instruments in the mm, submm, and NIR ranges.

 

[Richard Man]

Maybe they are allergic to F11 ;-P

 

[blockend]

Chinese lenses are often built for more than one format, so distance scales are largely fictional. Treat apertures on the same basis and you won't go far wrong. They tend to sharpen up across the field at smaller apertures than modern optics.

 

[bernard_L]

Chinese lenses are often built for more than one format, so distance scales are largely fictional.

Same lens, same focal lengtrh, same focal plane, same register distance.
So the distance scale stays the same. Ditto for aperture scale. (and why would f/11 specifically be left out?)
The only scale that "depends" is the DOF scale, since the acceptable circle of confusion is to a degree a matter of opinion; depends on the format and the sharpness expectations. This said, the distance between the f/22 marks should be 4x the distance between the f/5.6 marks, regardless.

 

[blockend]

Same lens, same focal lengtrh, same focal plane, same register distance.
So the distance scale stays the same.

I'm aware of the 7Artisans 25mm in Fuji fit. The same lens in m43 mount is said to have an accurate focus scale, while the X-mount is way off. It also lacks f11 aperture markings.