Dpic_arctic wrote:
Yes, right at the climax of the action. Fabulous idea.
Um, I could change lense faster than the zoom on your video camera, wanna bet?
Sorry guys...didn't mean to derail the conversation The popularity of HD DSLR's is growing fast but there's a long ways to go...right now to even get close to capturing good HD footage you need to spend a lot of $$$ on rails, folow focus, eye loupes, external mic, etc. etc. But one thing is for sure, primes,esp. fast primes are the most desired. I've invested some dough in this equipment and once I understand the post-workflow I plan to try to capture weddings along with my wedding photog friend.
Got my Rokinon in yesterday. Un-boxed it and tried this short video test w/o any practice:
I want to use it with my stock focus screen in my 5DMK2 for at least a week to get a feel for how it performs, or actually how I perform. I've taken some stills at 1.4 and I will say it's not easy using the VF, but in LV it works well using zoom but that's just not all that practical for me.
Then sometime next week I'll put in the EG-S screen and see how that feels.
Okay I installed the EG-S screen. Made a big difference in focusing capability but it's darker. My canon 100 2.8 is considerably darker but I still think I will find the new screen better to use.
Here's the issue now. Using the VF all on this Rokinon, Rokkor 58mm, and Canon 100mm all front focus some. I've researched some and it sounds like if I have some focus screen shims then I should remove some to correct the front focus issue.
I always forget which way the screen needs to go to correct for front vs. back focus. Try removing the shim and see what happens. If the front focus gets worse, then you need more shim. If it changes to back focus, then you need a thinner shim.
P.S. You'll get used to the slightly darker VF. I installed mine on day 2 of owning my 5D and never looked back. It is a small price to pay for focusing accuracy.
cogitech wrote:
I always forget which way the screen needs to go to correct for front vs. back focus.
Think of the screen as a replacement for the sensor. If your focus is in front of the subject, the sensor is too far from the lens. So then you'll have to move the sceen so that its distance is the same to the lens as the sensor is, which is away from the lens.
Yeah, I've understood all of that several times and it always makes sense. Then I promptly forget it. I blame it on my extracurricular activities at university.
So since the shims are above the focus screen they are moving the focus screen closer to the lens and if my focus is in front of the subject i.e. front focusing then I need to add more shim material rather than less.
I've used slivers of scotch tape successfully in the past, but it may not be the perfect thickness for your particular setup. Worth a try, though. Just be very careful when handling the screen. Hold it only by the edges and wear "finger condoms" if you have them.
lextalionis wrote:
So since the shims are above the focus screen they are moving the focus screen closer to the lens and if my focus is in front of the subject i.e. front focusing then I need to add more shim material rather than less.
I’ll see if our local camera shop sells the shims or maybe use some clear tape?
Thanks,
Roy
Describing all of this can get confusing, at least to me. If you are saying that the actual captured image from the camera is front focused when it looked sharp to you in the view finder, then you would need to move the focus screen away from the mirror (it is too close), which would mean using a thinner shim, not a thicker one.
lextalionis wrote:
So since the shims are above the focus screen they are moving the focus screen closer to the lens and if my focus is in front of the subject i.e. front focusing then I need to add more shim material rather than less.
No, as Mark says you'll have to remove a shim or replace it with a thinner one. Remember the simple rule of focus getting closer as you set the lens farther away from the sensor or screen. Your screen is closer to the lens than the sensor! So you must move it backwards (which is upwards due to the mirror).
I hope I'm thinking clear here. You can always try by just removing the shim and see what happens, as per Cogitechs confusion argument.
Just a quick update on my front focus situation. I wanted to get a baseline of all the lenses I use before calibrating. In summary...all of my MF lenses (Oly, MD, Kiron, Rokinon) all front focus about the same. Now all my Canon EF AF lenses seem to be spot on or just slightly front focusing.
My 5DMK2 had two shims, a thick and thin in relative terms...they're pretty thin. So I decided to take the thinnest shim out first. Results of this were slight back focus. To prove my sanity I decide to leave the thin in and take out the thickest. Results were major back focus.
So with both shims I was getting moderate front focus. With just the thickest shim I was getting slight back focus. The ticket for me was placing very slim strips of masking tape (cut with a razor blade) on each side of the thick shim. Now I'm 98% spot on.
I think the take-away for this is that everyone should test their MF lenses and MUST calibrate if they are off. Now for more testing and playing.
I got my Rokinon too. I am loving it! It has some CA wide open, but I understand that that is typical for a lens this fast. It is a small challenge to MF, but the EF-S screen really helps a lot. This is my first "alt lens" and it is a truly unique experience. Doing everything manually is actual not that bad. What I like the "permanent DOF preview" is that you are reminded constantly which aperture you are using. It keeps you more aware of the current settings.
I only have three complaints that I can think of.
1.) The lens is so fast that I cannot use a fill flash in daylight. (1/250 max x-sync on 40D).
2.) The aperture is not recorded (f/00), so I can't go back to old photos and review that f/stop in the exif data. Minor inconvenience...
3.) The lens hood is hard to mount (already mentioned by some). As some already said, inexpensive replacement hoods are available.
Dpic_arctic wrote:
1.) The lens is so fast that I cannot use a fill flash in daylight. (1/250 max x-sync on 40D).
Yeah, why can't cameras have built-in ND filters for things like this... Seriously, it would be possible!
Dpic_arctic wrote:
2.) The aperture is not recorded (f/00), so I can't go back to old photos and review that f/stop in the exif data. Minor inconvenience...
You'll learn to estimate the aperture used pretty fast
Per Dpic_artic complaints etc. I can second the notion of some (IMHO moderate) CA wide open, but not really worried about it as I can eaisly correct in post.
Having a good time with the lens for sure. I just ordered the Mark II version of the Vari-ND filter from LCW since I can't even begin to film in fast apertures even in the shade (stuck with the 180 degree shutter constraints of 24p which equates to a shutter of 1/50th).
The popularity of HD DSLR's is growing fast but there's a long ways to go...right now to even get close to capturing good HD footage you need to spend a lot of $$$ on rails, folow focus, eye loupes, external mic, etc. etc. But one thing is for sure, primes,esp. fast primes are the most desired. I've invested some dough in this equipment and once I understand the post-workflow I plan to try to capture weddings along with my wedding photog friend.
