Focus Assist

jeffreaux2

I had a shoot that went on to after dark last weekend. I had a problem getting solid focus on a shot that I tried and tried to execute......using the STE2 with an OCF and the 70-200mm zoom. I ended up too far from the subject for the STE2's assist to be of help, and had placed my subject in a dark area to avoid hassles with color temp of an existing light fixture nearby.

My question.....since I had a halogen flash light in the truck...is....should I have lit her face with the flash light....obtained focus....then turned the flashlight off and taken the shot. I dunno why that wouldnt work....any ideas?

Of course I could have grabbed a shorter lens too, but I liked the compression I was getting with the longer focal length.

Heres what I was able to get.....for example purposes....




This is where I ran into problems....

Wil Davis

I don't see why using a powerful flashlight wouldn't work as a focusing aid.

Were you using a tripod? Could you have approximated the focus (the wall on her left [camera right] looked to be in focus); use that as a starting point - something in the same plane as her face, and bracket a dozen nearer and a dozen further away changing focus fractionally each time (sort of like stacking) and then choosing the best of the bunch.

Use LiveView and manual focus, and "zoom-in" (magnify) to get the focus pin-sharp.

Did you have an assistant? …could be used to hold chequered or patterned board in the same plane as model's face to use as a focussing aid…

Unless it's action or sports, I always try to use manual focus…

HTH -

- Wil

BTW - Gorgeous model…

Sam

The short answer is yes. I have used this in a few situations.

Sam

Art Scott

I agree with Sam, remember to lock your focus before turning off your focus aid......another option is to find a shorter focal lenth to shoot outdoor portraits with

jeffreaux2

Wil Davis wrote:

I don't see why using a powerful flashlight wouldn't work as a focusing aid.

Were you using a tripod? Could you have approximated the focus (the wall on her left [camera right] looked to be in focus); use that as a starting point - something in the same plane as her face, and bracket a dozen nearer and a dozen further away changing focus fractionally each time (sort of like stacking) and then choosing the best of the bunch.

Use LiveView and manual focus, and "zoom-in" (magnify) to get the focus pin-sharp.

Did you have an assistant? …could be used to hold chequered or patterned board in the same plane as model's face to use as a focussing aid…

Unless it's action or sports, I always try to use manual focus…

HTH -

- Wil

BTW - Gorgeous model…

Using a tripod outside of a studio....especially with today's stabilized lenses for on location portraits is pointless....and won't help to focus the camera.

A checkered board would have also been in complete darkness....and would be of no assistance unless it were lit.

Through my own tests....I have determined I cannot focus better in manual than the AF system can focus.....except of course for the rare macro work I do.

I think in this circumstance the flash light is the answer.

jeffreaux2

Sam wrote:

The short answer is yes. I have used this in a few situations.

Sam

I like this short answer....especially since you have backed it with experience.

Thanks

jeffreaux2

Art Scott wrote:

I agree with Sam, remember to lock your focus before turning off your focus aid......another option is to find a shorter focal lenth to shoot outdoor portraits with

I have shorter lenses that could have done the job, but the compression of the background....especially in the full length shot is what I was going for.

I never imagined when I purchased it that it would become my primary lense choice when shooting on location portraits, but it has earned its place. I rarely shoot smaller than F4 and mostly shoot F2.8....and my favorite trick is to do a seated pose in landscape orientation where I can really back up and shoot at the longer end of it to fill the frame for that ultra compressed look and shallow DOF. It creates a look that is unachievable with any standard prime or zoom.

The bokeh is bonus.

Thanks Art.


Oh...and yes....my arms are in good shape!



What about the modelling light function of the 580EX/EXII? I avoid using it due to reports of fried units, but for an instant that MIGHT also be a readily available focusing aide......ya think?

pathfinder

You had the wrong lens - you just needed the 200mm f2.0 L - then you would have been fine

I think the 580ex might have worked to achieve focus lock also. But a flashlight would be fine also.

angevin1

jeffreaux2 wrote:

What about the modelling light function of the 580EX/EXII? I avoid using it due to reports of fried units, but for an instant that MIGHT also be a readily available focusing aide......ya think?

Well...I am glad I 'd not heard that about the modeling light funx. On my Nik I use it all the time, just to see where the light is. In fact, I do it over and over if I am having to adjust and whatnot....No issues so far! Just to be clear, we are talking about the flashes modeling light function: ie; I press the DOF preview button and the flash or flashes light up like a fast-strobe-disco ball showing me where they are pointed?

cheers,

jeffreaux2

pathfinder wrote:

You had the wrong lens - you just needed the 200mm f2.0 L - then you would have been fine

I think the 580ex might have worked to achieve focus lock also. But a flashlight would be fine also.

Send that 300mm over and Ill report back with a confirmation on that!

jeffreaux2

angevin1 wrote:

Well...I am glad I 'd not heard that about the modeling light funx. On my Nik I use it all the time, just to see where the light is. In fact, I do it over and over if I am having to adjust and whatnot....No issues so far! Just to be clear, we are talking about the flashes modeling light function: ie; I press the DOF preview button and the flash or flashes light up like a fast-strobe-disco ball showing me where they are pointed?

cheers,

Yes....that is what I had referred to.

It can create a lot of heat. Use wisely.

ziggy53

If you do use a bright flashlight I suggest using a red filter for the flashlight. The red is still pretty easily seen by the camera's AF sensor, but it won't be as blinding for the subject.

Pathfinder is correct that the Canon 580 EX series flash units has a more powerful AF assist light than any other flash I have tested. It also seems to focus the light into a more collimated beam for longer focal length lenses. Compared to a flash light beam it is also a "projected pattern" meaning that it has a pattern to make it easier for the camera's AF sensor to detect critical focus.

angevin1

jeffreaux2 wrote:

Yes....that is what I had referred to.

It can create a lot of heat. Use wisely.

Will do!

On the flashlight thingy...I have used that a time or two, in-house and find tripod mounted and using live view for it to be a PITA. I think one less item to contend with would be a boon just for the ease of moving thru the scene on Location. One would think a flash light would be so easy, but it hasn't worked that well for me so far.

The red filter over the flashlight trick, eh Ziggy? Sounds like a Boy Scout FL~:D

Yeah, and the Military too~ Works~

ziggy53

angevin1 wrote:

... The red filter over the flashlight trick, eh Ziggy? Sounds like a Boy Scout FL~:D

Yeah, and the Military too~ Works~

Also used in astrophotography and telescopy, even some darkroom processing (red 1A filter). Pretty much any time you need to see basic shapes in the dark and have your eyes recover quickly. Guilty of association to all of these at one time or another

pathfinder

jeffreaux2 wrote:

Send that 300mm over and Ill report back with a confirmation on that!

You didn't need more reach but more aperture.

jeffreaux2

pathfinder wrote:

You didn't need more reach but more aperture.

Yes I know...I "got it".......I thought it funny you tried to sell me on a lense when I asked about using a flashlight.....


A tad descrepency in cost.


Honestly though...I doubt that even my 50mm F1.4 would have grabbed focus where I had her stood without some sort of assist.

Next chance I get Ill try this....and report back!