To get selective focus you need to be further away from your subject not close in.

The things that affect DOF are

Lighting - Having the aperture wide open (low light) gives you shallow, while tons of light (aperture just a pinhole) gives you great depth

Zooming in - telephoto compresses DOF, wide angles expand it. When you see those shots in movies (think Tony Scott movies) where the subject is isolated against just a blur, they are using really long zoom lenses and they are zoomed all the way in.

The size of film frame/chip You wont be able to change this, but bigger camera chips have shallow DOF. Just as 35mm film has a Shallower DOF than 8mm film does.

Thanks everyone for the advice.

As much as I accept Bob my superior I do disagree with this. I think the eye travels to the the area of most focus and so is happy to go from a really out of focus distant tree to a half out of focus hair to a fully focused eye and enjoy the journey.

oh my what an interesting duscussion this turned out to be.

I have to confess, i too am a cheat...
The cookie cutter and quick/gausian blurs are my friend..
Fake rack focus', tracking racks etc etc are some of my guilty activities.

Yes it can look fake sometimes, but hey, if you can make it work while looking fake, wll the power to you.

cookiecutter allows for a moving focal range and twaekng gausiian allows oen ot manipulate the distortion.
For a more precise "feel" using Velvet matter, with its defocus filter is really quite nice as you can emulte the camera iris blades and nuance to blur within that iris F stop setting... pretty nifty

I guess the cookie cutter/bezier mask and gaussian blur method works best with the camera on a tripod? (Or else tons of painstaking keyframes would be involved.)

This site http://www.jetsetmodels.info/tutorials.htm looks promising, but I'll probably won't have enough time (or knowledge) to construct this adapter before I have to begin shooting again. But it definitely looks like it's worth a try for future use.

"I guess the cookie cutter/bezier mask and gaussian blur method works best with the camera on a tripod? (Or else tons of painstaking keyframes would be involved.)"

Not really... depends on how good of a shooter you are...

u dont really need a tripod if you knowwhat shots you want ot mess with..
put it this way, i shoot all my wedding preps handheld until i get the ceremony. Once there, i use a monopod and the second cam is on tripod. Photohsoot is handheld, and reception is handheld till speeches. Speeahces i use a monopod for B roll and Tripod for A roll.

If you know your camea and it nuances with its OIS, then you can get away with ALOT
With an A1 at full wide, you can also get some pretty crasy steadicam type shots

When I'm shooting stills of computer parts or spring wildflowers I find that where the eye travels is not necessarily to the point most in focus (and so I focused on the wrong point).

Usually my eye travels to the most meaningful or resolvable detail. For flowers it's the pistil/stamen area, for a graphics card it may be the end connectors or may be the biggest text object, for people it's usually the eyes or maybe the thing in their hand.

Graphics cards are the most interesting example to me because my eye always travels to the detail I can identify. Circuit board traces could be most in focus but my eye would go to text first because it has more meaning.

Selective focus often isn't enough to control what people look at, I think.

Rob Mack

>>>Selective focus often isn't enough to control what people look at, I think.<<

Absolutely correct. Composition, lighting, and action are the primary tools. Restricted DoF is a refinement and is great for separating the subject from a cluttered background. But if the other elements direct attention to some out of focus object, that's where the eye goes and is discomforted by not being able to bring it into focus; you might use that discomfort for dramatic effect before racking focus. Think of shallow DoF as giving emphasis in well executed composition.

You might want to check this link, it's a Letus mini 35mm adaptor attached to an HV20, impressive footage and camera.

http://www.philipbloom.co.uk/Philip_Bloom/HV20__Letus_Mini_test.html

I own a Letus Extreme, still have my old Letus 35a, they are awesome tools!!!

Rob

That is awesome footage; thanks for the link. Phillip said he should have had the Letus Mini mounted on rails as the HV20's threading is a little weak to hold all that weight. (not the picture I get from Letus' website! http://www.letusdirect.com/cart/Letus35-Mini-p-21.html )

You own a Letus extreme; would you say its only difference from the mini is the available threading size? Or does the extreme have better performance?

Also how would you (or anyone else reading this) compare the Letus 35 Mini to the Redrock Micro M2, Brevis 35, Cinemek G35, SGpro, etc.

I know the Mini for sure flips the image around which is a definite advantage; some of the others mentioned above need adapters that are extra $$$.

I do believe that the only differences between the Extreme and the Mini are the threading size, but you might want to double check with LetusDirect or check out their forum. They are very efficient!

I basically did some intensive search on all available models. Few years ago, I had purchased the Letus 35a for my PD170, it was the best priced adapter, low light loss, but no flip, still, I fell in love with it! Once you put it on your camera, you don't want to remove it anymore! And shooting on a ground glass just adds to the film look, it is not as crude as pure video.

Brevis, I am not so pleased by their video samples, it seems that their are achromatic abberrations, I don't like their bokeh. I did like the M2 sample videos, but it is bulky and not so pratical to use on the field.

So I decided to stick with Letus again and purchased the Extreme for my EX1. The video samples are just incredible. Mind you that with an HD camera, focus is more critical, handheld is still a challenge, but I am working on it. They did have a problem with the EX1, but now they have a new achromat specially designed for the EX1 and it proves to be just great. I still have to order mine. Low light loss, about half a stop and it flips your image! It is easy to install, brilliant conception, but heavier than my previous adapter, which couldn't handle HD.

I was fortunate enough to get a hold of the Redrock M2 adapter. It's great. Old Nikon fast lenses off ebay ... cheap etc etc etc. Have a look at the trailer and my production stills gallery for shots of my rig if you want.

www.thesilentwomanmovie.com

(I'm now in the process of trying to keep Vegas Pro 8 stable enough to finish my first indie feature.)

Good luck with your search for control of DOF and AOV. If you don't need it for a shot just take the adapter off.

Cheers,

Darren Powell
Sydney Australia

Someone commented one needs to zoom in about 3/4 with the HV20 to get rid of all the vignetting on the Letus 35 mini.

Does this mean I would have to stand further away from the subject?

One last question: What would be the best lens for use with the HV20 and Letus 35 mini that would allow for a wide range of uses at a reasonable price? (Phillip Bloom used the Zeiss T2 50mm macro)

I know it's probably a matter of taste, but I have no expertise when it comes to lenses, so I would be totally lost! :-)

Thank you again for all your expert advice, I really appreciate it.

No matter what, you have to zoom on the ground glass, it is like cropping your shot so you only see what is on the ground glass and not the inner parts of the adapter. No matter what system you buy, it is a required ajustment. You don't have to stand further, it won't change your lens perspective. But can also set it in order to get slight vignetting, which can add to certain themes.

A good lens to start with is a 50mm f1.4, I have a Nikon lens, got it used for $70, nice and sharp. It is considered a normal lens, falls in between the wide range and the telephoto range. If you want to get tight shots of peoples faces, you might want to get an 85mm or 105mm.
You can also use your 50mm and zoom in on your ground glass to get a tighter shot. But if you physically get too close to a person's face with a 50mm, you will get some slight wide angle distortion on the face.

Remember that you will want to work wide open depending on the quality of your lens to about f5.6, after that, the grain on the ground glass becomes more and more visible.

You might want to check out this link where you can see a video of the inner part of a Letus Extreme and give you a better understanding....

http://web.mac.com/stevecahill/Steve_Cahills_Blog/Blog/Entries/2008/2/12_Letus_EX1_Fixed.html

Rob

The field of view is determined by the lens used on the adapter. Your video camera fixed lens is just looking at the image on the Letus "ground glass", so it doesn't matter what focal length that is set to (in terms of the FoV) provided it takes in all the image on the glass. In essence the attachment includes a close up lens that allows the camera to focus on the glass. One issue that is affected is the effective aperture: your camera lens will ramp in f/number as you zoom to tele, so generally you would wish to be able to employ full aperture when necessary. Important to consider this when defining light losses inherent in using these things.

Thanks everyone for the insight; the video helped too.

--Rob: How close with a 50mm will generate barrel distortion? Phillip Bloom was fairly close in his demo video and everything looked good (his lens was a macro, so I guess that means it's designed for close-ups?). I'd like to be able to do shots like in his video.

If you are doing portraits, tight facial shots, you might get some deformations of the face, making what is closest to the lens appear bigger. That is why photographers use 85mm or bigger focal length for portraits because they minimize facial distortion. Using wide angle lenses and getting closer to your subject will accentuate deformations.

If you want to do macro, using non-macro lenses, I use an extension ring (PK-11A) for my 50mm Nikon lens. This way, I can easily get close-ups of flowers, few inches away from my subject, and I haven't noticed any achromatic or barrell distortion, only very very narrow depth of field! Mind you that a macro lens will probably give you better results because it's been designed for this matter, the extension ring is a great alternative. I use it for artistic work and not scientific work, and it is a very creative tool combine with a 35mm adapter!!!

Thank you for your expert advice and tips.

It's great to be able to talk to someone with first-hand experience when one is still learning about the whole realm of film. That's why I appreciate this forum so much.

Even those using the "fully professional" 2/3 inch sensor cameras (which are in fact 16mm sized) use the Letus-type adapters when they want "35mm DoF", so some of that experience might be of interest and hopefully they will tolerate being quoted:

William B. Demeritt, III
Camera Dept (AC, Op, grip/elec)
New York, NY
"I work with a DP in the city that owns a Letus35. So far, I'm fairly impressed with it. The cost is far cheaper than the P+S, as you've seen, but also the light loss in the actual module is significantly less than the P+S. Along with the cheap cost of the unit are the cheap lens mounts (significantly lower than the P+S prices across the board, if I recall).

Another DP I know owns an SGPro, which is also super low cost 35 adapter, but that device merely offers the spinning ground glass with no prism, so you record an upside-down image, mandating an onboard video monitor that can flip the image (or mounts upside down). The Letus35 feels like a fairly solid unit, although many of the standard screws attaching the Letus to the baseplate come loose.

Of the miniature 35 adapters I've worked with, I think the Letus35 is the best deal running. None of the light loss of the P+S, more solid than the SGPro, cheap lens mounts, solid unit, etc. In the next month, I'm expecting to work with the Letus35 again, only this time with cine lenses (previously worked with some Nikon still lenses where none of the witness marks were accurate), and only after that will I really sign off on the whole unit.
=============


Leonard Levy
DP San Francisco Bay Area"

"Having used all the popular 35mm lens adapter systems and run side by side tests with the 4 popular inexpensive Nikon systems I think you can get very good results with all of them. Though I'm calling them Nikon systems , actually all have interchangeable mounts and can adapt to PL.

In particular manufacturers of the Brevis , the SgPro and the Letus Extreme have been racing with each other in R&D and continue to make improvements (virtully monthly these days) in build quality and sharpness. At this point all three now produce good right side-up images with good sharpness corner to corner. They all lose significantly less light than the P&S, and are much lighter and easier to handle. I wouldn't hesitate to use one instead of a P&S but I haven't run any side by side tests against the P&S.

The units each have their pros and cons because they use different mechanisms and different imaging screens. They generally lose about 1 stop or less of light at f1.4 and the fastest of them, the Brevis can use a quality 2.8 Nikon zoom @ 2.8 with still less than stop loss of light. You can find imaging screens that have more and less diffusing characteristics and it is possible to go handheld without killing yourself. I for instance generally find the P+S too heavy - both in pounds and in the amount it diffuses the image.

Right now they work on most of the 1/3" cameras but each of those cameras has their quirks so research would be advised. The Sony EX lens has thrown them a curve and so far only the Letus (as of this
week) and perhaps the SGPro has redesigned an achromat to adjust to it, but very soon the Brevis expects to have one ready as well.

They may tend to be a little light weight and quirky for rental house use and you need to make sure your 35mm lens back focus is correct.
As with a lot of equipment if you don't know what you're doing you can produce inferior pictures, and because of the price point these attract inexperienced people.

Personally I think the least troublesome and the best image quality overall comes from the SGPro made in England. I would use this any day in preference to a Mini35."