Manual Focus Woes in bright sunshine

[Chris Harding]

Hi Guys

I just did another wedding yesterday and the main camera has a Tamron 17-50 F2,8 on it and damn! the ceremony main shot is significantly softer than the cutaway shots. It's totally usable of course and I can sharpen it easily but it annoys me that it happens. It's obviously the fact that it's me and not the camera and more than likely it's not focussed 100% ....we are talking here about really bright sun where the camera with the manual lens full open makes the camera wants a shutter speed of anything up to 1/6000th!
I naturally stop down on the adapter to keep shutter between 1/50 and 1/100th but then the aperture is going to be probably f11 or even smaller which means I have a massive DOF and even using expanded focus at 8X it's hard to nail it perfectly with peaking.

Now, here's the question ... would peaking be more accurate with the lens fully open at F2.8 than stopped down at F16?? If it is then should I be setting up the camera, keeping the lens iris full open and getting focus perfect and THEN close the iris to get a respectable shutter?? Does peaking take DOF into consideration so at F2.8 it's only going to peak at a smaller area and at F16 the peaking highlights will show up almost everywhere???

I did some simulations in the back garden and it appears that footage looks sharper if I nail focus with a smaller DOF and then stop down. Doing speeches in the venue with the same camera is no problem at all as I need to be full open normally and those images are sharp.

Maybe I need a variable ND on the camera so I can use big apertures, so I can get focus more accurately or should I put a laser rangefinder on the cold shoe and get the exact distance??

Which method do you use to get an accurate manual focus?

Chris

[Peter Rush]

That's a good point Chris - You'd need to run some tests but I would definitely focus wide open and then stop down - seems like that should work. I know I shouldn't really but I use the old 'zoom to focus' technique that I used with my ENG cams (Panny DP800 and JVC DV500) that had parfocal zooms, the reason is that even on paper they are not - my Canon 24-105 and Tamron 24-70 are actually pretty much parfocal

Best Lenses for DSLR Video (Parfocus Lenses) - Bristol Freelance Video Editor/Camera/Production (Cameraman) South West England UK

I used a Genus variable ND filter for a while until I dropped and cracked it but I found it introduced a colour cast and sucked some DR out of the image so have not replaced it - were I to use ND again I wouldn't go with a variable.

I've just completed a short corporate shoot and as well as relaying on the EA50 peaking I used my SmallHD monitor mounted on the shoe which has very accurate peaking as well - maybe this is an option?

[Noa Put]

I"m almost sure what you did experience was lensdiffraction, if you keep the shutter at 1/50 or 1/100 and don't use a ND filter in bright sunlight the only way to compensate is to close the down the iris as much as possible which will give you a large dof but even if you had your focus right, the diffraction caused will make the image look soft and out of focus.

Most lenses perform best around f4.5 which should give you the most detail for setting focus but as long as you don't close down the iris almost completely it doesn't really matter that much at what aperture you are at as the f-stop determins you dof and that is something you choose to select your dof. I would avoid closing down your aperture as much as possible.

[Chris Harding]

Thanks Pete and Noa

I figured as much! Yeah it's really hard to tell in bright sun whether the aperture does affect the peaking but I think it does! So it's obviously more accurate to focus at F3.5 - F4.5 rather than F16 plus put up with the diffraction

I too had some unfortunate issues with colour casts on expensive ND filters too! I'm surprised the Genus has colour casts! What I normally do is run at a slightly higher shutter on bright day weddings as there is so little movement as they stand there that you can get away with a 1/600th shutter without any freeze or stutter and that pulls the aperture down without having to use an ND filter... I got tired of having red casts in my image anyway!!

Chris

[Dave Baker]

Hi Chris,

I agree with Pete and Noa, but to add my two penn'orth, I suffered colour casts using Cokin ND filters, not sure whether they're considered a good brand or not although I thought they were, even though I white balanced with them in place. I swear they softened the image too, but then I've never liked anything in front of my lens (apart from the subject!) anyway, apart from in exceptional circumstances.

Diffraction starts at f11 with an APS-C sensor, so I was trying to keep below that with 1/50th shutter on sunny days.

Yes, I too found peaking works better with the lens wide open. It gets more difficult with smaller sensors, although that can be alleviated quite well by zooming in if it's a zoom lens.

It's one of the reasons I hate cameras without an EVF.

Dave

[Chris Harding]

Thanks Dave

It is a bit frustrating as the main cam has an F2.8 lens and I sorta weigh up the best setting between shutter and aperture. At F2.8 on Saturday the camera needed 1/6000th shutter WOW ..yes it was super bright so I ended up guessing an F-stop that would be around F8 (on my adapters there are no graduations so you just have open and close so I try to work somewhere around mid way) I honestly think what I did was stop right down and then focus and I should have done it the other way around as at say F11 the DOF would have been massive and the peaking would have even indicated the background trees 50m away!! Funnily enough I had my 10-24 Tamron on the 2nd cam for cutaways and bridal entry too and all that footage was razor sharp ....Think it was purely an operator error ... Hmmm maybe I should buy a 50' tape measure? They use them in the movies ..however the lens barrel distance between 7 metres and infinity is so tiny one would have to guess any distance further than 7 m! but that is roughly how far back I was from the couple so just a tiny twist left or right means a soft picture .... My follow focus unit is geared down a bit ..maybe that would help too? When the barrel only has a few mm between distance points one might be more accurate with a geared system as long as there is no play ... I must try that!

Chris

[Michael Liebergot]

Chris I wanted to resurrect this post because I had the same issue the other day for a speech that I filmed.
Unfortunately the ballroom that I filmed the speech in was entirely wrapped with floor to ceiling windows which made it impossible for me to not shoot against a backlit background. Due to space I didn't really have room to mount any lights so I was stuck with trying to film and fight with the backlit background.

Well even with some blind pulled I had a focus issue with my EA50M with stock and 17-150mm f4 Sony lens, as peaking said was focused but after reviewing my footage I wasn't close. The backlight made it hard for the camera to get a proper exposure. I am able to add some sharpening in post to correct this but it really ticked me off after the fact.

Wish I would have brought some ND gel for the windows which might have helped considerably.

BTW my other camera Sony NX5U did;t have nearly the problem and worked pretty well. Although this was my closeup camera so I did;t have to fight with light as much as the wide cam EA50M.

[Chris Harding]

Thanks Michael

Yeah I think the peaking falls to pieces if you are shooting a backlit situation and sadly most lenses have very little leeway between 6' out and infinity .... I guess the answer should be trust the camera ..since you were using the M series stock lens, did you think about trying the LCD touch focus ??? It seems to be very accurate? Of course on a manual lens you have to just guess the distance!

Chris

[Michael Liebergot]

Chris of course I thought about it after I reviewed the footage. As I assumed that all was well with focus.
Of course you know what they sayvaboutvwhen you as some... =)

[Chris Harding]

Yeah it gets really scary when you get home and review the footage and it's all soft !! Not a good feeling at all ... surely if you use the stock lens on camera and kick in autofocus it will be accurate enough??

[Steven Digges]

Hey Michael,

In a ballroom situation I would have my SmallHD 7" monitor on top. It is indispensable in that situation. I use it all the time. I also use expanded focus a lot to check focus. Small viewfinders just aren't enough for critical focus in that situation.

Chris, An external monitor won't help much, if at all for all of the outdoor weddings you do but I would still try one with a hood. Depending on where the sun is they can still help. Obviously if back lighting is the problem shot it wont be shinning on the monitor.

Many years ago I shot a ballroom speech with a Canon XL2 and a cheap 5" low res monitor of the day. Those cameras were terrible about focus searching in AF. I knew that very well so my system was to use manual focus and "pull" focus by touching the AF button. On this day I did not realize I had accidentally left the AF switched to on. For a one hour speech the camera was searching the entire time between her nose and her ears or something like that. In out, in out, in out. I could not see it on the monitor but it never stopped. Someone here has how I felt in their signature: "The horror of what I saw on the timeline was indescribable!" I have had few disasters in my career but that was one of them. It was totally ruined and I lost sleep over it. I tell the ugly story to say MONITOR the image the best way you possibly can! I have a low end Marshall 7" and the Small HD 7". I am not sure the SmallHD was worth three times the money over the Marshall but I would buy five of them to avoid wrecking just one job!

Steve