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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 :)

What I learned today getting my Scarlet and lenses checked by a lens tech.

Brian Iannone said:
By familiar, do you mean familiar to the images you were seeing before you had your Scarlet's backfocus adjusted?
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Yes, exactly what I mean.

Brian Iannone said:
Aha, I do indeed love tech! That's something that I'm definitely adding to my shopping list. :-)
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The RED Focus only works with PL mounts. Maybe RED has a Canon version in the works... If a 3rd party got on this and made an affordable tool like the RED Focus for Canon mounts I have a feeling it would sell like crazy.
 
Brandon J.F. said:
With a Canon mount/lens I have no idea. I have a PL mount. Hopefully someone posts here with some advice for you guys with Canon mounts. I'm curious as well.
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Backfocus adjustment procedure on Scarlet/Epic is the same regardless of mount, as the adjustment moves the sensor and not the mount.
 
ericyoung said:
Backfocus adjustment procedure on Scarlet/Epic is the same regardless of mount, as the adjustment moves the sensor and not the mount.
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Yes, I know that. I just know that if you are doing it manually you need precise lenses. We used Vantage (Leica) and Arri Ultra Primes. I have no idea which Canon lens someone should use. I also don't know of any devices like the RED Focus to help simply the process for those with Canon mounts.
 
Brandon J.F. said:
Yes, exactly what I mean.



The RED Focus only works with PL mounts. Maybe RED has a Canon version in the works... If a 3rd party got on this and made an affordable tool like the RED Focus for Canon mounts I have a feeling it would sell like crazy.
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Optitek Optimator is available with interchangeable PL, Canon EF and Nikon mounts. But, assuming all your lenses are the same or very close to correct backfocuswise, then do the adjustment with your widest lens.
 
ericyoung said:
Optitek Optimator is available with interchangeable PL, Canon EF and Nikon mounts. But, assuming all your lenses are the same or very close to correct backfocuswise, then do the adjustment with your widest lens.
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Well, there is your answer Canon Mount guys...

Thanks Eric!
 
Thanks guys, this is all very helpful.

Red, I'd love to see a Canon Mount Version of the Red Focus, do you have any near plans for that?
 
Ted Parkes said:
Checking and adjusting back focus is necessary from time to time and particularly / mandatory when switching between mounts. Should be part of your regular camera prep.
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Indeed. In fact, I would go beyond that statement. In order to have good focus, there is a holy trinity: focus of the lens to subject, collimation of the flange focal distance (FFD) and, backfocus of the sensor (to the correct FFD). Looks like the OP hit the trifecta of errors, at least on the 35, and hit 2 out of three on the 22, and 1 of 3 on the 50 and 150. All three have to be accurate, and I mean accurate to the 1/10,000 of an inch, in order to achieve proper focus.

Devices to check these are called autocollimators. They are not cheap and, they themselves need to be calibrated. The RED Focus is a type of collimator, but is dedicated to one mount type (PL) and only checks the camera to mount backfocus. The other two, FFD collimation and focus scale tick marks need to be done by a pro.

The camera's backfocus can go out with not just different mounts, but over time. Even changes in temperature can affect the backfocus setting because of the thermal expansion of metals.

In short, Scarlet/Epic are not point and shoot cameras. They are Ferraris that need constant attention. Likewise lenses need to be CLA'd and fairly often. As the OP found out, even if he had the backfocus set up correctly for one lens, the other lenses need match the first in terms of FFD and scale in order for that backfocus to remain valid. Some people shoot on zooms to save either the time required to reset the BF with every lens change, or to save $$$ on collimating an entire lens set.

You pay either way, its just a question of when, where , and how much.
 
Go to page 221 of the Scarlet Manual for backfocus instructions. It's done with a Red Focus, but if you have your own siemens star and a lens you trust, or the one you use, you can at least get it very close.
 
I just did another test. Does this look like a back focus issue or just a soft lens issue to you?

sharpness_sample_2.jpg


TIFF (18MB): http://www.brianiannone.com/scratch...checked_by_a_lens_tech/sharpness_sample_2.tif
R3D (2MB): http://www.brianiannone.com/scratch...checked_by_a_lens_tech/sharpness_sample_2.zip
 
if i'm not mistaken you should be able to get a sharp picture even if your back focus is out by using the 'punch in button' to get focus, correct? just means your lens focus marks will be off and your infinity focus may not be precise. also means your zooms function more like variable primes.
 
scott william said:
if i'm not mistaken you should be able to get a sharp picture even if your back focus is out by using the 'punch in button' to get focus, correct?
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That's what I thought... Which is why I'm thinking that the Canon 24-70mm f/2.8L lens that I'm using is extraordinarily soft and the Scarlet's back focus is fine.

By the way, what do you mean by the "punch in button?"
 
Brian Iannone said:
That's what I thought... Which is why I'm thinking that the Canon 24-70mm f/2.8L lens that I'm using is extraordinarily soft and the Scarlet's back focus is fine.

By the way, what do you mean by the "punch in button?"
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I think he means the 1:1 focus assist punch in.

Yeah your image is still soft even when I added sharpness and contrast.
 
Brian Iannone said:
That's what I thought... Which is why I'm thinking that the Canon 24-70mm f/2.8L lens that I'm using is extraordinarily soft and the Scarlet's back focus is fine.

By the way, what do you mean by the "punch in button?"
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Hey Brian,
I recently took my 24-70 2.8 into canon's service center in irvine, it was soft and since getting it back it has been significantly better, I'd consider doing this although it costs about $150 dollars. Do you have a prime you could test in the meantime to compare sharpness?

I'd shoot two focus charts, focused by eye using the 1:1 punchin. One with a prime and one with your 24-70, if you post both I'll take a look at them and let you know what I think.

-Jacob
 
Brian ,
How much does stopping down to f5.6 or f8 help?
You know how I feel for you in respect of sharpness issues!
 
Thank you for the info Andy. It seems that to be a responsible & empowered owner, acquiring & learning how to BF with Red Focus is a must. How does the PL fitting of the RF impact us Canon mount guys? Can anyone describe or link to the process of setting BF? Thanks again.

EDIT: never mind ;) I read the scarlet manual has instructions for this & for canon mount guys theres this thread...

http://www.reduser.net/forum/archive/index.php/t-33998.html

Andy White said:
Basically, it's common that, before a big shoot, you'd get your camera checked (and all your lenses)... the step into the big leagues offered by the Scarlet just means new owners have to get used to some more normal practices :)

In the old days (don't forget - I'm an old timer - LOL) a DP (no matter how major league) wouldn't own a camera. That's where the rental house comes in... and why they're setill important on big projects now. They have guys or access to experienced techs and make sure kit they send out is shoot ready.

The big growth in owner/operators driven by the first RED wave a few years ago, simply meant that a lot of these guys started to acquire skills to make sure they knew how their kit works.

Remember that RED stuff is high-end - and has a cost implication sometimes... especially when you're taking your first steps :)

http://www.red.com/store/accessories/product/red-focus - this is Red's tool for backfocus adjustment - I know from your posts you love tech, so something else to look at ;) (Brian, that is :)
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Hey Brandon, how much did the shop cost (to set back-focus specifically.) I don't want to sound critical either, but I certainly feel that, direct from RED, the back focus should be properly set... is it something that could get shifted in shipping?

Also, could you not just get any lens, set focus distance via markings (assuming your lenses aren't janked up) and then slowly adjust the backfocus until the image is sharp? Wouldn't that suffice (especially for non-cine glass)?
 
Mike P. said:
Hey Brandon, how much did the shop cost (to set back-focus specifically.) I don't want to sound critical either, but I certainly feel that, direct from RED, the back focus should be properly set... is it something that could get shifted in shipping?

Also, could you not just get any lens, set focus distance via markings (assuming your lenses aren't janked up) and then slowly adjust the backfocus until the image is sharp? Wouldn't that suffice (especially for non-cine glass)?
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The back focus setting is probably correct leaving Red and even when you first get your camera. The issue is more likely to be your lens IMHO. Even with the back focus out you should be able to get sharp focus, just the focus marks will not read correct distance on a prime lens. On a zoom focus will be off as you zoom through the range, but you can still set it correctly for whatever distance you are shooting at. Having you back focus set correctly for your lenses does make shooting much simpler.
 
Matt Ryan said:
Yeah your image is still soft even when I added sharpness and contrast.
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Thanks for confirming, Matt. :-) I've been trying everything I can to sharpen the image, but it appears to be unfixable. I can see that my issue is indeed with the lens now.


J Taylor said:
Hey Brian,
I recently took my 24-70 2.8 into canon's service center in irvine, it was soft and since getting it back it has been significantly better, I'd consider doing this although it costs about $150 dollars. Do you have a prime you could test in the meantime to compare sharpness?

I'd shoot two focus charts, focused by eye using the 1:1 punchin. One with a prime and one with your 24-70, if you post both I'll take a look at them and let you know what I think.

-Jacob
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I got a Ti Canon Mount with my Scarlet because I was planning on using the 24-70mm I have until I'm able to get a prime lens, but based on the results I'm seeing so far, I may end up just replacing the Ti Canon Mount with a PL and getting an RPP sooner rather than later.

Unfortunately, I don't have a prime lens I can test it with.


Les Dittert said:
Brian ,
How much does stopping down to f5.6 or f8 help?
You know how I feel for you in respect of sharpness issues!
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I've tried f/5.6, f/11 and f/23, but they all produce the same soft image. I'm going to take a the 24-70mm and put it back on a Canon 7D to see if I'm still getting soft images from that. I don't recall if in the past, my photos were this soft though...
 
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