Bower 14mm weird behavior ---SOLVED !!!!

[NWPhil]

So finally I got my hands on a bower 14mm, in preparation to a Canon ef 14mmL II loaner trial.

Sure I was aware that focus and aperture are manual, BUT as I switched the aperture ring back and forth,from 2.8 to 22, no light change did happen.
I tried a few times, and nothing, till I gave the lens a light tap on the side, when the value was at f/22.
The viewfinder did become darker as it should be. I turn the ring to 2.8, and it did become lighter, but as I turn it back to 22, again no light change on the viewfinder
The light tap solved the problem.

No, I am not kidding, but has annyone ever experienced similar situation with this lens ( knock-offs included)?
It seems that the lens has some issues...

Thanks for your feedback

 

[koolman]

Re: Bower 14mm weird behavior

I own the bower (Samyang) 14mm + used with my 550d.

Superb Lens. Always use in AV.

Never had such as issue.

 

[NWPhil]

Re: Bower 14mm weird behavior

Thanks
I guess you mean Tv? the manual aperture ring controls the aperture, and is not registered by the camera sensor.
Truelly, you can shoot in manual or shutter speed only.
Thru the viewfinder, does the brightness changes, as you turn the aperture ring in the lens?

Thanks

 

[sheedoe]

Re: Bower 14mm weird behavior

I am having one of those delivered to me today. If I see such issue, its going straight back for an exchange. I heard of decentering and other such quality issues with some copies of this lens, but nothing like you have described. Sounds like something is causing the aperture blade to be hesitant in opening and closing.

 

[Mt Spokane Photography]

Re: Bower 14mm weird behavior

Take it back. Mine resulted in images with the entire left side smeared. I've never seen a lens with this poor of quality. QA is poor, so its hit and miss.

I've seen almost as many complaints as those with praise.

 

[NWPhil]

Re: Bower 14mm weird behavior

Indeed - everything else is fine. The best way to describe it, is to say the aperture blades are getting stuck - wich then makes sense having a light tap fixing that.
Anyone knows which models have the AF confirmation chip?

 

[qwerty]

Re: Bower 14mm weird behavior

I caused a similar problem myself on a Samyang 14mm.

I had removed the mount so that I could glue a focus confirmation chip onto it (to keep the superglue away from the glass). In the process, I inadvertently knocked something in the aperture adjusting mechanism loose (can't remember what it was now, and do not have the lens in front of me to check).

It wasn't too tough to figure out what the problem was and it took me less than 5 minutes to fix it; I seem to remember something spring-loaded being a bit finicky, and that it was easiest to have the aperture blades either wide open or stopped down to get everything in place. (Sorry; I know how awful vague descriptions are when you are trying to troubleshoot, but this was a long time ago for me.) I haven't had any issues since doing the repair. If you are mechanically inclined, it might be worth a shot; if you are not the type to do lens surgery, you can probably exchange the lens.

My 14mm has been outstanding all-around.

 

[pdirestajr]

Re: Bower 14mm weird behavior

Thanks
I guess you mean Tv? the manual aperture ring controls the aperture, and is not registered by the camera sensor.
Truelly, you can shoot in manual or shutter speed only.
Thru the viewfinder, does the brightness changes, as you turn the aperture ring in the lens?

Thanks

I think you have that backwards. You shoot in AV.

IE: You adjust the aperture (on lens) and the camera's meter chooses the shutter speed. Or you can shoot in manual. I'm going to assume you can NOT shoot in TV (never tried). In TV- you choose the shutter, & the camera chooses the aperture. Since the aperture is manual on the lens itself, there is no way for the camera to choose the aperture for you.

 

[NWPhil]

Re: Bower 14mm weird behavior

That's why M - manual is the way to go - but, here's the thing : In Av mode, the camera is not reading the aperture values, as the lens does not communicate electronic with it.
In my case, it did not allowed me to change the shutter speed at all, unless I used the compensation button and then dialed up and down to over or underexposed.
With Tv mode, I set the aperture in the ring, and then I can dial the shutter speed to control the exposure.
Maybe I am completly wrong, or it's another issue with the lens, but could not really control the exposure in Av

Qwerty:
I did not touch anything in the mount. Seems that the lens does not have the Af chip anyway, because indeed I don't get my AF points to light up. The spring thing seems to be a good explanation, but I am not going to play with it, as it's not my lens. Thanks

 

[NWPhil]

got the lens to the store, and they were able to confirm that indeed the aperture blades were getting stuck, as the ring got turned - so it's not a camera or shooting technique issue.

The lens needs to be send for servicing, more exactly lubricated.

The few shots I took, they did come out sharp and with a nice IQ, but now I question the reliability of this lens. Is not too old, and cosmetically, looks like a 9.5.
So, I suspect it can happen any given time to annyone - maybe storage temperatures do play a role, or is just a poor quality control.