How close will my lens focus?

snaggs · Mar 24, 2007

I have just ordered a 400mm Tele-Xenar from Badger, and before they ship the order, I'm wondering if I should get them to add a bellow extension for my Tachihara.

My Tach has a max of 330mm (some say 315mm) and the 400mm requires 285mm for infinity.. I thought this would be enough, but didn't realise I would need more to focus closer.

One use of this lens would be for tight head shots.

Daniel.

naturephoto1 · Mar 24, 2007

Hi Daniel,

You can get an Ebony Top Hat Extension Tube set also from Badger Graphic. The Ebony board is a Linhof Technika Type Board. The tubes for the board as I recall are either 17 or 35mm in length. You would probably need the board, 1 35mm tube and the I believe #1 cover for the Copal #1 Shutter. The set as described costs about $130 US. That should yield about 65 to 80 mm to focus between the tube and the bellows. If you feel you need more, you can get additional tubes that screw together.

See this link:

http://www.badgergraphic.com/store/cart.php?m=product_detail&p=1146

Rich

David A. Goldfarb · Mar 24, 2007

Wista makes a top hat extension lensboard that comes with three tubes and three plates for Copal 0, 1, and 3 shutters, and you can add more rings or if you use it a lot for many different lenses, you can get more plates.

But try it first. You may have enough already for what you want. Have you tried tight headshots with the 210mm? You may find that it works for you. I often shoot portraits with a 210mm lens on 4x5".

snaggs · Mar 24, 2007

Rich, good idea, something that might be enough, however the 400mm lens has a Copal 3 shutter.. so I don't think that one will work.
David, thanks, I'm looking for a nicer working distance. I remember trying with a 240mm lens in the past and you really had to get quite close!

The bellows in my first post is $300, about the same price as the Wista set I saw on BHPhoto.. I'm not sure how the bellows extension fits on though.

Daniel.

naturephoto1 · Mar 24, 2007

Hi Daniel,

My error, I thought that the lens used a Copal 1. You can get the same set that I mentioned, but substitute the #3 Cover instead of the #1. The Covers for the Top Hat are available as #0, #1, and #3. Additionally, the board can be used with a cover directly mounted on the board and then used on the camera if the extension is not required. Again the same price and the same page for the link. Just send an e-mail to Badger requesting the size that you want. If you wish to get the bellows from B&H you can, but I do not know the stability and how it is attached to the camera. Additionally, unless you have a board for the Copal #3 shutter you will need one. They would run about $30 or so dollars. So on that basis, if you purchased the Ebony Top Hat extension the tube and cover are basically only costing $100. As to the Wista set that David mentioned, as I recall, though more included, it runs somewhere around the cost of the bellows extension from B&H.

Rich

jonw · Mar 25, 2007

David A. Goldfarb said:
Wista makes a top hat extension lensboard that comes with three tubes and three plates for Copal 0, 1, and 3 shutters, and you can add more rings or if you use it a lot for many different lenses, you can get more plates.

I agree with David. I have a tachihara 4x5 and picked up this extension item on ebay for about $60. Although they are few and far between, it fits nicely on the Tachi. Without it, it seems the maximum lens I am able to use for my purposes was 300 or 305mm.

Jon

snaggs · Mar 25, 2007

Jon,

So how does the bellows mount on the Tachihara? Is it stable?

Rich,

The top hat sounds like the best option, as I only need the extension for one lens.. so that way, the lens/board/top hat are all integral. The only question is.. will that give me enough extension?

There hasn't been a reply yet with a formula etc to work out what I would need to use the lens say as close as 1.5-2 metres. Maybe the tophat will be enough.. maybe not.

At least the bellows would let also proove usefull should I want to goto a 800mm Nikon or something later in the future for landscapes, but then it is alot more bulky than the tophat solution.

Daniel.

David H. Bebbington · Mar 25, 2007

snaggs said:
There hasn't been a reply yet with a formula etc to work out what I would need to use the lens say as close as 1.5-2 metres. Maybe the tophat will be enough.. maybe not.

The classic "conjugate distances" formula states:

1/u + 1/v = 1/f

where:
u = Object (subject) distance
v = Image distance (camera extension)
f = Focal length (back focus)

For a back focus of 285 mm, the closest achievable subject distance with 330 mm bellows extension is 2089 mm.

Regards,

David

snaggs · Mar 25, 2007

David H. Bebbington said:
The classic "conjugate distances" formula states:

1/u + 1/v = 1/f

where:
u = Object (subject) distance
v = Image distance (camera extension)
f = Focal length (back focus)

For a back focus of 285 mm, the closest achievable subject distance with 330 mm bellows extension is 2089 mm.

Regards,

David

Fantastic David! Looks like I can get away with just a tophat!

eddym · Mar 25, 2007

David H. Bebbington said:
For a back focus of 285 mm, the closest achievable subject distance with 330 mm bellows extension is 2089 mm.

Which, with a 400mm lens, will yield a field of view of 480x626mm. Not quite what I would call a tight head shot, but you have plenty of film real estate to crop from if you don't mind doing that.

snaggs · Mar 25, 2007

eddym said:
Which, with a 400mm lens, will yield a field of view of 480x626mm. Not quite what I would call a tight head shot, but you have plenty of film real estate to crop from if you don't mind doing that.

Ok, but with a 35mm extender.. I have a max extension of 365.. which means I can focus as close as 1.3 metres (1300mm).

What field of view will that get me? I know the DOF will only be .94 cm which should be pretty nice creamy backgrounds if I need to blur them!

Daniel.

eddym · Mar 25, 2007

snaggs said:
Ok, but with a 35mm extender.. I have a max extension of 365.. which means I can focus as close as 1.3 metres (1300mm).

What field of view will that get me? I know the DOF will only be .94 cm which should be pretty nice creamy backgrounds if I need to blur them!

Daniel.

Hi Daniel,
The formulas for field of view are as follows:
Width of field= ((distance-focal length) x width of image)/focal length
Length of field= ((distance-focal length) x length of image)/focal length

The image size on a 4x5 negative is about 96x120 mm, so with a 400mm lens at 1300mm, you have
((1300-400) x 96)/400= 216mm wide;
((1300-400) x 120)/400= 270mm long.

Pretty tight. Don't forget to allow for your total bellows extension in calculating your exposure adjustment.

PS- With 9mm of dof, are you going to use a head brace to be sure the subject doesn't move after you have focused?

snaggs · Mar 25, 2007

eddym said:
The image size on a 4x5 negative is about 96x120 mm, so with a 400mm lens at 1300mm, you have
((1300-400) x 96)/400= 216mm wide;
((1300-400) x 120)/400= 270mm long.

Pretty tight. Don't forget to allow for your total bellows extension in calculating your exposure adjustment.

PS- With 9mm of dof, are you going to use a head brace to be sure the subject doesn't move after you have focused?

Yay... now were talking! I don't always like to shoot with a blurry background.. but I do like to have the option..

With regards to a head brace.. can't you all hand hold a view camera with a 400mm lens and focus on the eyes?

Nick Zentena · Mar 25, 2007

snaggs said:
The bellows in my first post is $300, about the same price as the Wista set I saw on BHPhoto.. I'm not sure how the bellows extension fits on though.

Daniel.

$300 should be more then enough to get you an older 5x7 with a 4x5 back. You'll have plenty of bellows and won't need to go the telephoto route.

Amund · Mar 25, 2007

You worry too much about background blur, and personally I would`t buy that 400mm you have ordered, you`d be off to a better start with a 210mm IMO.

Another example on background blur on 4x5, this is shot with a 150mm f/5.6 wide open.

snaggs · Mar 25, 2007

Thanks Amund. Yes I am being a worry wart, its just my in-experience. I know what a 135mm f/2 does on 35mm, I know what a 85mm f/2 does.

That is a nice example, but the background isn't very busy and is far in the distance.

Daniel.

eddym · Mar 25, 2007

snaggs said:
With regards to a head brace.. can't you all hand hold a view camera with a 400mm lens and focus on the eyes?

Well of course!! I do it all the time with my Technika V, thanks to the wonderful Linhof anatomical grip, rangefinder, and multifocal viewfinder!!
OK, so I cheat... I use a monopod!
OK, so I'm lying, the longest lens I have cammed for the Tech V is a 180, f5.6 Symmar S. But yes, I can handhold it and focus on the eyes with the rangefinder.

But my friend, I do have to wonder if you realize that 9mm is a helluvasmall dof... especially when you consider that in order to truly obtain it, you will have to focus 3mm inside it, so that you have 6mm behind the plane of focus and 3mm in front! Let's see, if you focus on the near eyeball, the tip of the model's eyelashes might just barely be in focus, whilst the far eyeball will be lost in that creamy fog you seek.

I'm dying to see you post these headshots!

All seriousness aside, good luck and enjoy your new lens!

HerrBremerhaven · Mar 25, 2007

At his 1.32m distance, his DoF works out to about 32mm (using pCAM software on my PalmPilot). That might be enough to get the nose and eyes in focus on most people, with everything else out of focus. Of course, he might need lots of light to keep exposures reasonably short.

With a 210mm at the same camera to subject distance, he could shoot at f5.6 to get a close matching DoF (35mm). Unfortunately, to get a tight headshot like with the 400mm, he would need to be closer, and run into DoF problems again, forcing stopping down more, and again exposure timing issues (depending upon lighting).

Once I plugged some numbers through pCAM software, and previewed the shots, it seems to me that his choice of a 400mm is better than using a shorter lens. I don't think he is going to have an easy time doing these shots, but the results might be interesting if he can get it all to work.

Ciao!

Gordon Moat
Dead Link Removed

eddym · Mar 25, 2007

HerrBremerhaven said:
At his 1.32m distance, his DoF works out to about 32mm (using pCAM software on my PalmPilot). That might be enough to get the nose and eyes in focus on most people, with everything else out of focus. Of course, he might need lots of light to keep exposures reasonably short.

With a 210mm at the same camera to subject distance, he could shoot at f5.6 to get a close matching DoF (35mm). Unfortunately, to get a tight headshot like with the 400mm, he would need to be closer, and run into DoF problems again, forcing stopping down more, and again exposure timing issues (depending upon lighting).

Once I plugged some numbers through pCAM software, and previewed the shots, it seems to me that his choice of a 400mm is better than using a shorter lens. I don't think he is going to have an easy time doing these shots, but the results might be interesting if he can get it all to work.

Ciao!

Gordon Moat
Dead Link Removed

Hi Gordon--
Don't have a Palm, so I have to do the math on a calculator.
But I don't get 35mm, nor do I get his 9.something mm. Using a .005 inch circle of confusion, I come up with about 15mm dof at f5.6 at 1300mm distance. That's from about 1293 to 1308 mm.
Using Linhof's more critical .0038 inch circle, I get almost 12mm; from about 1294 to 1305.
Either way, it's not much, and he'd better convince his sitter not to flinch between the time he dives under the dark cloth and when he pulls the slide and snaps the shutter!

HerrBremerhaven · Mar 25, 2007

Okay, as best I know, pCAM software adjusts for changing CoC based upon film sizes. At 1.3m is a very close headshot. Using f5.6, that gives a rounded off figure of 8mm DoF. Stepping down to f22.0 gives about 30mm DoF. My earlier numbers were computed at a greater camera to subject distance, which will help DoF issues. Perhaps the difference in numbers is that pCAM software uses a more critical CoC.

So I checked again using DOFMaster software on the Palm Pilot. That allows modifying the CoC, though the default for 4x5 is 0.1000mm. Using the default, and the 1.3m distance gives about the same DoF as with pCAM, so I suppose 0.1mm is close; also lands between 0.0038" and 0.005". Anyway, the point, as you indicated, is that the DoF will be very short, regardless of calculation or software.

Functionally, this reminds me of recent Chuck Close and Jerry Spagnoli daguerotype images, and the wet plate collodion work of Robert Benson. Several of those images are up close headshots, and with sitting times of 2 seconds or longer. All of those individuals mentioned lighting issues, DoF issues, and the difficulties of working with people. While higher ISO film might help, there are still going to be issues of long exposure times, and short DoF. All those issues will make getting good images really tough.

It would be possible by having the subject sit or lean against something. The subject would need to not move forward or backward. I have done larger than headshots at slow shutter speeds using a 4x5, so it is possible to accomplish this, though it is definitely not easy. Going into this expecting some mistakes might alleviate any anxiety.

Ciao!

Gordon Moat
Dead Link Removed

snaggs · Mar 25, 2007

Hopefully my Elinchrom Ranger RX heads will help me out with the light issues! Dificulty aside.. I can always stop down to f/11 or something, and the working distance much nicer than trying to convince them everything is safe and normal with a huge view camera 50cm from their face

Daniel.

eddym · Mar 26, 2007

HerrBremerhaven said:
It would be possible by having the subject sit or lean against something. The subject would need to not move forward or backward. I have done larger than headshots at slow shutter speeds using a 4x5, so it is possible to accomplish this, though it is definitely not easy. Going into this expecting some mistakes might alleviate any anxiety.
Dead Link Removed

Yup, thus my question about the head brace!
And yes, we are talking just a few millimeters of dof here.
I hope he tries it, and posts the results here. It would be interesting too, to try things like using swings to try to get both eyes in focus if the head is at an angle to the plane of focus. What would bother me would be the big fuzzy nose between the eyes...

eddym · Mar 26, 2007

snaggs said:
Hopefully my Elinchrom Ranger RX heads will help me out with the light issues! Dificulty aside.. I can always stop down to f/11 or something, and the working distance much nicer than trying to convince them everything is safe and normal with a huge view camera 50cm from their face

f11 might be a good compromise.
Go for it, Daniel!

eddym · Mar 26, 2007

snaggs said:
Hopefully my Elinchrom Ranger RX heads will help me out with the light issues! Dificulty aside.. I can always stop down to f/11 or something, and the working distance much nicer than trying to convince them everything is safe and normal with a huge view camera 50cm from their face

Hey Daniel, check out the portraits in this thread:
(there was a url link here which no longer exists)

How close will my lens focus?

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