why is my focus ring not working?

[ph0toe]

yes i did, i picked a focus length of 50mm. i backed away from the subject (being the object), i autofocus then switch to manual focus and then i moved closer and adjust the focus ring and it isnt sharp.

 

[SquarePeg]

how much closer? 1 step? 1 inch? Try it without moving closer. Can you focus manually then? I can't really think of any circumstances where auto focus would work and manual focus adjustments would immediately make it blurry unless you are either moving the af ring too much or moving too close. Maybe you should post one of these blurry photos along with your settings.

 

[weepete]

Is your lens able to manually focus with distant objects? Say 300ft or so.

 

[petrochemist]

yes i did, i picked a focus length of 50mm. i backed away from the subject (being the object), i autofocus then switch to manual focus and then i moved closer and adjust the focus ring and it isnt sharp.

As has been pointed out earlier it's NOT 'focus length' of 50mm, it's a focal length of 50mm (close to the field of view of he eye). If you can focus on things at least 2 foot away all the way out to infinity the lens is working fine. This lens doesn't focus close up, 'moving closer' is your problem - with the lens zoomed to 200mm it will make items look closer while still being further away.

 

[ph0toe]

Dropbox - IMG_0612.MOV - Simplify your life

 

[wfooshee]

I have no idea what you were trying to show us in that video, or why we had to have the second half of it looking at the floor.

The 50 on the lens IS NOT the distance to the subject!!!! The distance to the subject is in that little window on the top of the lens barrel.

Also, zooming in the display in Live View is a digital zoom, and getting "blurry" is normal for that. It's not really zooming, it's enlarging a section of the image, blowing up pixels and all as it does so.

If you're thinking you can focus on something that 50mm away from the lens, then you need to reset your expectations. The closest it will go is whatever the smallest number is that shows in that windows on top of the lens.

 

[ph0toe]

I tried refilming and reuploading.. but it keeps crashing
anyways, yes i am aware that the 50 on the lens is not the distance, it is just the focal length. at 50mm, its basically what the human eye sees. any less makes it wider and everything seen and any higher makes it possible to take a picture very far away (telephoto)

so the number on the focus ring indicate the distance to subject from the smallest being .7 to infinite.
now my question is why am i unable to turn the focus ring knob and get it in focus? i thought it was problem with the diopter but i set it so my eyes can see very clear through viewfinder..

 

[weepete]

It's possible that your focus ring is broken, but you should try and rule out human error first. Most often people don't realise that you have to be a decent distance away from the subject for lenses to focus, unless you are using a specialist macro lens. So it's very common to see that error.

You should establish if your focus ring works at all by trying to manually focus on something much further away. If it doesn't it's probably broken, but if it does focus on something far away, you are probably still too close to your subject and need to move the camera back.

Bear in mind that modern focusing systems in modern cameras are really meant to be used with autofocus, and are not as easy to use with manual focus as the old split prism viewfinders. Though there are times when MF can come in useful.

 

[wfooshee]

Does that number in the window change when you turn the focus ring? Does it change if you allow the lens to autofocus on something very far away, and something just a few feet away. Can you shift that focus with the focus ring?

All of this should be done looking through the viewfinder. I'm still of the opinion that using Live View to focus isn't telling you anything, as "zooming" in on the live View image is not really zooming, it's just enlarging and pixelating.

 

[SquarePeg]

OP you haven't really answered any of our questions - you keep posting the same info/statements. Can you manually focus on something far away?

 

[petrochemist]

I'm still of the opinion that using Live View to focus isn't telling you anything, as "zooming" in on the live View image is not really zooming, it's just enlarging and pixelating.

If your screen resolution is less than the sensor resolution there's no pixelation on initial zoom.
My eyesight is not bad, but I certainly find it easier to check focus on a zoomed screen, portions that look sharp enough in the viewfinder are often soft when printed to A4. Zooming the live-view image can enable focus to be pinpointed.
My experience with hundreds of manual lenses confirms it works brilliantly!

 

[wfooshee]

Agreed, but it depends on how far you zoom, and I'm frankly not trusting the information we're getting from the OP. I use Live View zoomed in to focus on infinity for astro photography.

My statements about his zoom are based on, "It gets blurry," which I'm interpreting as, "It gets pixellated."

 

[petrochemist]

Agreed, but it depends on how far you zoom, and I'm frankly not trusting the information we're getting from the OP. I use Live View zoomed in to focus on infinity for astro photography.

My statements about his zoom are based on, "It gets blurry," which I'm interpreting as, "It gets pixellated."

Thanks for the explanation, your interpretation is somewhat different than mine, but you could be right. If the OP shares some examples we should be able to tell

 

[stevet1]

ph0toe,
Do you have the lens electronic MF enabled in your menu settings?
If so, I think you have to press your shutter button halfway and hold it , or your AF-On button and hold it in order for your manual focus to work (assuming you still have the switch on your lens switched over to AF.)
Steve Thomas

 

[ph0toe]

Does that number in the window change when you turn the focus ring?

YES

Does it change if you allow the lens to autofocus on something very far away, and something just a few feet away. Can you shift that focus with the focus ring?

so i find that for autofocus instead of manual focus, if i go too close even when zoom in i am unable to take a picture because im assuming its due to the distance. when i move further away, i am able to.

All of this should be done looking through the viewfinder. I'm still of the opinion that using Live View to focus isn't telling you anything, as "zooming" in on the live View image is not really zooming, it's just enlarging and pixelating.

i find that when i "zoomed" in using the zoom lens i constantly have to adjust to get it in focus/sharp. is this normal? why cant i hold focus at say my desginated 35mm ?