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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

SALT II results... (Part 1,2,3,4 Bokeh, Breathing & Flare and Part 5: Impressions)

In regards to Macro lenses, I love my Canon 100mm f2.8 L Macro lens.

Very nice for portrait work, as well as macro work.
 
How do I tell if the Back-Focus is off on my Epic-X?

Sorry for the off-topic.

I'm assuming that even if the Back-Focus is off that I will still be able to sharply
focus the shot, but that the distance markings at that focus point won't match the
real world distance.
 
Martin, use the widest, fatest lens you have and set the sensor plane on a tripod at a marked distance from a focus chart. Use the 1:1 mode and either the focus or outline modes to help you determine if the image is sharp at the marked distance (6 feet is a good staring place). If your three widest lenses tape out correct you're probably good. If you have a zoom you'll notice that the focus will not hold through the range if the backfocus is out. Unless of course it's a still lens and then it just may not be parfocal.
 
So many people have no idea about this. So when we buy RED lenses, can we return them?

Costco FTW.

Les Dittert said:
That's why you can't buy lens's on ebay .... they are the rejects from guys like Ketch ! ;)
Click to expand...
 
KETCH ROSSi said:
Same thing with Cine lenses, you need to calibrate them, and makes sure that the back focus is set properly on the camera, and not touched.
Click to expand...

How exactly is this done?
 
Thanks very much to all of you guys for this test.

Yep, i agree... they're so close!!!

Really like my Duclos Cine-mods ZFs and his 11-16mm here!

The ultra lightweight of these lenses is a major PLUS for me :)

Antoine
 
Evin Grant said:
Martin, use the widest, fatest lens you have and set the sensor plane on a tripod at a marked distance from a focus chart. Use the 1:1 mode and either the focus or outline modes to help you determine if the image is sharp at the marked distance (6 feet is a good staring place). If your three widest lenses tape out correct you're probably good. If you have a zoom you'll notice that the focus will not hold through the range if the backfocus is out. Unless of course it's a still lens and then it just may not be parfocal.
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Evin,

Also, what i often do is to point the widest lense i have to the moon, set the lense at infinity and adjust the trim until the image is tack sharp :)

Antoine
 
OptiTek said:
I always wonder why anybody would use a macro lens designed for, uh, macro photography and optimized for close up work for normal distances. There are lenses designed for normal work....:wink5:
And BTW I know how these lenses look -I've projected lenses for 25 years- it's my business....
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True. The Contax 60 2.8 1:1 Macro lens is optimized for Macro and portraits. But it's well known to be soft at infinity and is not designed for landscapes. The Contax 100 2.8 1:1 Macro however is sharp at infinity, and can handle both jobs with aplomb. So not all macro lenses are compromised.
 
Setting the backfocus on a lens needs to be done at an optical facility or a camera house with a lens collimator.
 
Mitch Gross said:
Setting the backfocus on a lens needs to be done at an optical facility or a camera house with a lens collimator.
Click to expand...

I understand that this might be the BEST way to do it, but I assume that it is not the only way.
 
Evin Grant said:
Martin, use the widest, fatest lens you have and set the sensor plane on a tripod at a marked distance from a focus chart. Use the 1:1 mode and either the focus or outline modes to help you determine if the image is sharp at the marked distance (6 feet is a good staring place). If your three widest lenses tape out correct you're probably good. If you have a zoom you'll notice that the focus will not hold through the range if the backfocus is out. Unless of course it's a still lens and then it just may not be parfocal.
Click to expand...

THANKS EVIN
 
It's important to mention that you have to be absolutely sure that your lens marks are correct. otherwise you are setting incorrect base line for your system and all bets are off...
 
I will say that yes, you need to use a lens you know is calibrated correctly to check the body backfocus and I would not use still lenses for this. The Optitek Optimator is also very useful if you change mounts often. It is certainly possible to do yourself but only if you have the knowledge and understanding of the limitations. Since I have my lenses checked out every 6 months or so I feel confident using them to check the camera. However the Titanium PL mount of the Epic is very solid and I have yet to even need to adjust mine.
 
Heh heh. Thanks for adjusting my backfocus with the Optitek Optimator Evin. Appreciate it!
 
Martin Stevens said:
I understand that this might be the BEST way to do it, but I assume that it is not the only way.
Click to expand...


No, it's the only way. Certainly one can work his or her way to a somewhat correct backfocus on the camera using a properly set lens. But there is no way to collimate a lens itself without the correct tools. A collimator costs many tens of thousands of dollars and the precision shims used to set the mount are measured in microns.
 
Mitch Gross said:
No, it's the only way. Certainly one can work his or her way to a somewhat correct backfocus on the camera using a properly set lens. But there is no way to collimate a lens itself without the correct tools. A collimator costs many tens of thousands of dollars and the precision shims used to set the mount are measured in microns.
Click to expand...

What he said. But really it's a rather precise process filled with lots of trial and error based off years of experience for professionals. I've got a lot of respect for anyone who can correctly set back focus for their own lenses.
 
I'm sot saying it's a good idea, but myself and many a 1st AC has had to make a "Field adjustment" to a lens that just wasn't holding focus. Certain lenses like older Cooke zooms are easier than others, I woukdn't crackopen a Master prime or Leica Summilux-c which I hear can only be calibrated with a laser (can anyone confirm this?).
 
Mitch Gross said:
No, it's the only way. Certainly one can work his or her way to a somewhat correct backfocus on the camera using a properly set lens. But there is no way to collimate a lens itself without the correct tools. A collimator costs many tens of thousands of dollars and the precision shims used to set the mount are measured in microns.
Click to expand...

Okay, but then what is the Red Focus product from Red for?
It does not cost many tens of thousands of dollars.

Perhaps collimating a lens is different than collimating a camera sensor/or moving the camera sensor.....if that makes any sense.

What I was really trying to ask earlier was if your backfocus if off a bit can you still get sharp imagery
with your lens even though the lens distance marking will not match the real world distance?

Or in other words, if your lens had NO markings on it, could you still get a sharp image even if the
backfocus was off a bit?
 
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