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DSLR 101 3.0

jazzman1
Rising Star

 

 

 

1 ACCEPTED SOLUTION

jrhoffman75
Legend
Legend
Unless there is only one item in your viewfinder, which is next to impossible, there are an infinite number of distances between you and the items.

Only one distance is in perfect focus, and depending on depth of field, a range of distances will be in acceptable focus.

Zooming the lens doesn't change the distance anymore than it compresses the distance between objects.

Maybe it's my imagination, but I often feel a tugging on my leg when I read some of these postings.
John Hoffman
Conway, NH

1D X Mark III, M200, Many lenses, Pixma PRO-100, Pixma TR8620a, Lr Classic

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44 REPLIES 44

 

This is a article, I think, is refuting DOF as I understand you guys are explaining it.  I'm not saying it is, I don't know...I'm learning.   Is he, "Ken", saying the same thing you guys are, or is his take a different spin on DOF???     Your feedback of what Ken says here would be very helpful..

 

 

 

 

 

http://www.kenrockwell.com/tech/focus.htm

Rockwell is OK but he is loose with details and accuracy soemtimes.

EB
EOS 1DX and 1D Mk IV and less lenses then before!

Thanks Obiwan, that's good info for me.  I did'nt know much about him and was reluctant to accept with he said on face value.  I do know ehough to not run with just anything I read online.

 I'm not sure which way the Canon 70-300mmL lens "Ring Mount" attaches to the lens the correct way.  I tried both ways with the foot  pointing backward toward the camera, and the opposite way, pointing out away from the camera.  Weight distrubution seemed best with the ring foot pointing forward away from the camera, but I want to make sure that's best way.  Which way is right, or is there a right and wrong way?   Their was no instructions in the box, and this is my 1st heavy L lens.

Pointing front.

EB
EOS 1DX and 1D Mk IV and less lenses then before!

I have to make an apologize to Canon for berating them for not putting instructions in the Lens Ring Mount box.  I'm just looking at the instructions (CD) that came with my EF 70-300mmL lens, and the ring mount instructions are included there.  No offense Obiwan, but as I said, did'nt make sense they would sell the Lens Ring without any instructions how to use it.  They do include instructions for the ring mount, but it's in the 70-300L manual (CD), included with the lens with instructions.  Guess they figure if you buy the ring mount, you already have the lens.  That's the only lens it's intended to go on.   I know you say it's a lens designed for Pro's and Pro's already know how to use it.  True, I agree with you there, but they also sell a fair amount of Pro Gear bought by non Pro's and instructions should be included for us.  Silly me, they do, you just have to look in the right place.   I'm right also cause the directions is included with the lens.  I already had tried the ring mount both ways and concluded facing toward the front was correct for the weight of the combo togather.   But I was not sure and wanted to double check with a Pro....You.

 

 

Again, apology to Canon for wrongly accusing you for something not true.

"...  the 70-300L manual (CD), included with the lens with instructions."

 

I have never looked at it.  I probably don't even have one.

 

"... they also sell a fair amount of Pro Gear bought by non Pro's and instructions should be included for us."

 

But you and those guys are not the intended market. That is why there is the black one!  I am sure Canon will sell to whomever wants their gear and I can also verify they will assist you in its use.  As a matter of fact, Canon is far better than most big companies.  Better than Adobe and better than brand-N. 

Besides it saves paper!

EB
EOS 1DX and 1D Mk IV and less lenses then before!

 

 

 

But you and those guys are not the intended market. That is why there is the black one!  

 

Yep, and I do intend to look into a few quality EF lens.  As I told you, I don't need all L lens for my purpose.  I have no intentions of becoming a Pro, so I don't need all my lens to be Pro level.   that's also why i got f/4 aperture in the 2 L's I have.  And I don't like the extra weight much.   I did want the 2 lens i did get to be Pro level lens, cause I'll proably use them togather the most.  I wanted a good foundation to build around.

 

You know since I've read alot of threads lately, about micro adjusting lens and lens out of focus, I checked my focus for the 1st time.   I turned on my camera settings to show me my focus points in the pics I take.  In several ranges from about 18mm to about 100mm, many of my focus points are way off.  Fom there to appox 200-300mm the focus points are right on, exactly where I focus in the viewfinder when I framed the pic.  Seems some of my close to mid range focus  points in my lens are off.  I don't know if my 60D has focus point adjustment, I'll have to look and see.  I know it does'nt have lens micro adjustment like you guys have in your high end bodies.  I hope there's some way for me to correct this.

Two things.

1st you may be hurting yourself by using EF lenses instead of EF-S lenses that your camera was designed for.  Just because it is a EF lens designed for a FF camera does not insure great sharpness on a cropper.

2nd, the focus could/can be user error.  Sorry but a more likely scenario.  Try again using just the center point.  Turn all the others off.  As a matter of fact I always use just the center point.

EB
EOS 1DX and 1D Mk IV and less lenses then before!

1st you may be hurting yourself by using EF lenses instead of EF-S lenses that your camera was designed for

 

I'll take that into account.  One day I'll have a FF body, and really did'nt want to invest in lens I could'nt use with both bodies.  In fact, you suggested I do that (get EF lens for compatibilty) when we 1st met and talked about the lens I should buy.

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2nd, the focus could/can be user error.  Sorry but a more likely scenario.  Try again using just the center point.  Turn all the others off.  As a matter of fact I always use just the center point

 

You could be right about user error.  I just got back from taking shots just to double check.  Many of my pics as I said from appox 18-150mm the focus points were off.  I tried all my lens, my EF-S and EF, non L's, all were the same, not just the 2 L's.  I always use my middle focus point, though the 60D has 9.  The pics that the focus point was on target, was dead on the center point, dead on.  When I got back and read this message I turned all 8 points off except the center point, as you've said. 

 

I won't be taking test shots till tomorrow.  When I turned off all the other focus points except the center point, it now says "manual".  in the menu.   When all nine was on it said "automatic" in the menu.  Now that I think about it maybe my lens focused on something closer than my target, like a tree branch.  I've noticed it has done that before.  A time or two my lens would'nt get a sharp lock on my intended target cause it was focusing on a tree limb or leaf that was closer. in my path of sight.   One of the outter points of the 8 around the center point had locked focus on a leaf or limb and my intended target at the center focus point was a tad out of sharp focus.   You know I practice my shots in the park alot and there's trees, flowers, plants, and bushes galore.  The only open clear area is by the water where guys fish along the rails, and a very few other spots.   And come to think of it sometimes one of the guys fishing line has caught my lens focus.   The more I'm thinking about it I'm inclined to believe it just may be user error.  Cause it's happening with all my lens, not just the 2 L's.   I may just step out my front door and take a few test shots.   Thanks much Obiwan (Thumbs Up)

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