Help me understand my Tilt shift lens for small items

swag72

swag72

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I am well and truely ready to throw this T&S lens out of the window, I am sure that there is something really stupid that I am not getting.

So, the scenario is this - Trying to photograph a chilli pepper in my light tent. I have got the 24mm T&S lens on as my understanding is that I should be able to achieve some good dof using the TS. I have the camera on a tripod, looking down on the chilli pepper. I understand that to maximise dof I should tilt the lens to try to maximise the angle between the lens and chilli pepper.

When I do this, it makes not a jot of difference to dof.

I remember seeing EdBray do a cool trick with a row of batteries at an angle and get them all in focus. Surely I am doing the same, but using tilt and not shift?

Can anyone help me make sense of this lens? Or am I doing something fundamentally wrong?

I have looked at the guides online, but maths was never my strong point and I knew I was alwyas going to find this difficult. I hope someone can help as this is the FIRST time I've put this lens on the camera and I've had it well over 6 months :eek: So, as you can guess, feeling despondant and a for sale thread coming on!!
 
To get everything in focus, lines drawn through the focal plane of the camera (sensor) the subject (the part of the pepper you want in focus) and the front element of the lens, should all meet at a single point. You may need to use the shift function (downwards in this case) to avoid vignetting.
 
swag72 said:
I am well and truely ready to throw this T&S lens out of the window, I am sure that there is something really stupid that I am not getting.

So, the scenario is this - Trying to photograph a chilli pepper in my light tent. I have got the 24mm T&S lens on as my understanding is that I should be able to achieve some good dof using the TS. I have the camera on a tripod, looking down on the chilli pepper. I understand that to maximise dof I should tilt the lens to try to maximise the angle between the lens and chilli pepper.

When I do this, it makes not a jot of difference to dof.

I remember seeing EdBray do a cool trick with a row of batteries at an angle and get them all in focus. Surely I am doing the same, but using tilt and not shift?

Can anyone help me make sense of this lens? Or am I doing something fundamentally wrong?

I have looked at the guides online, but maths was never my strong point and I knew I was alwyas going to find this difficult. I hope someone can help as this is the FIRST time I've put this lens on the camera and I've had it well over 6 months :eek: So, as you can guess, feeling despondant and a for sale thread coming on!!
Click to expand...

Okay, are you shooting directly down onto the chilli pepper?

If so, you will not benefit from the tilt to increase the depth of field.

Can you either do a drawing of your setup or take and post an image of it (camera phone will do if you have no other camera)?
 
[url=http://www.talkphotography.co.uk/gallery/showphoto.php?photo=95996][/URL]

Here's a pic of the set up. I am trying to use tilt to achieve back to front sharpness. I have looked on the net and the following was recommended.

1) Focus on point furthest away (Would be the end of the chilli pepper)
2) Use the tilt to achieve focus on the nearest point you want in focus as well (In this case the stem)

Am I expecting the impossible from this type of distance?
 
Looks okay to me, are you tilting up or down?

You need to be tilting down,
 
Canon Bob said:
Sara,

You may have already seen this tutorial but it specifically deals with what you're asking.

Bob
Click to expand...

Cheers Bob, will have a look.

EdBray said:
Looks okay to me, are you tilting up or down?

You need to be tilting down,
Click to expand...

I am focusing on the end tip of the chilli and then tilting .... Hang on let me go and check .................... I think I'm tilting up (well, the end of the lens is going upwards).

If I use the method as I mentioned above, a tilt in the opposite direction is rendering everything oof on live view.

Where should I be focusing on? Perhaps I'm doing that bit wrong :shrug:
 
Sara,

The first diagram on the link I posted is inter-active. Drawing your cursor down the column of figures ("Apply lens tilt") on the right and the diagram will show you where the plane of sharp focus will lie.

Bob
 
The front element of the lens should tilt in the same direction as the chilli is laying i.e the bottom of the front element of the lens should be nearer to the bottom of the camera than the top of the lens is to the top of the camera.
You may need to re-focus once you have tilted the lens.
 
That first diagram highlights nicely how tilting down increases the plane of sharp focus. So to achieve this the best of sharpness, where do I want to be focusing on the chilli pepper in my example?
 
A couple of questions Sara.....

Are you judging the focus wide open or using the DoF preview to see where it lies?

I assume that you're going to stop down for the shot? It really is essential at the distance you're shooting. Being used to a macro lens, I expect that you're thinking along the same lines but with the focal plane angled. Alas, it's not quite so simple. Your macro lens is a flat field design and will exhibit an absolutely flat focal plane. The TS-E24 isn't flat field due the the requirement to shift....you can imagine what would occur when the principal axis is not centred over the middle point on the sensor.

By stopping down at very close range, you'll mitigate some of the effects of the non-flat focal plane.

....it was difficult to write that sensibly....it makes sense if you already understand it :cuckoo:

Over to Eddie for a better attempt at rewording Herr Scheimpflug's ramblings.

Bob
 
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Sara...I've just emailed a pdf to you.

Bob
 
Canon Bob said:
A couple of questions Sara.....

Are you judging the focus wide open or using the DoF preview to see where it lies?
Click to expand...

I was using live view - As I focused on the part of the chilli pepper furthest away, I then used live view to see when the nearest part of the chilli pepper - the stalk - was in focus.

Canon Bob said:
I assume that you're going to stop down for the shot? It really is essential at the distance you're shooting. Being used to a macro lens, I expect that you're thinking along the same lines but with the focal plane angled. Alas, it's not quite so simple. Your macro lens is a flat field design and will exhibit an absolutely flat focal plane. The TS-E24 isn't flat field due the the requirement to shift....you can imagine what would occur when the principal axis is not centred over the middle point on the sensor.

By stopping down at very close range, you'll mitigate some of the effects of the non-flat focal plane.

....it was difficult to write that sensibly....it makes sense if you already understand it :cuckoo:

Over to Eddie for a better attempt at rewording Herr Scheimpflug's ramblings.

Bob
Click to expand...

I was using f/11. I am finding I am using this most of the time these days, even with macro as the IQ is markedly diffwerent as I stop down further.

So no need to worry too much with that with this lens?

I think what I am struggling with now is 2 things
1) how much tilt to use
2) where / how to focus
 
Sara,

With no shift applied, I think you'll find that when tilting the lens the focus won't change along a line half way up the frame. So if you try focusing there first, then tilt the lens so it points downwards (this will tilt the plane of focus down to lie along the line of the pepper). As you apply the tilt watch what happens to the focus at either end of the pepper. From that distance you will probably need a few degrees of tilt, but try a bit at a time. One of the best articles on the web I found on using tilt is http://www.northlight-images.co.uk/article_pages/using_tilt.html.

Jonathan
 
The closer you are and the more acute the angle of the camera the greater the amount of tilt you need to apply. At a rough guess and looking at your setup I would think you would be needing between 6 and 8 degrees of tilt.

I would focus midway along the chilli and then add your tilt, using the liveview check your focus, I would do this at the open aperture and then once I have the plane of focus along the top of the chilli, I would adjust it slightly so as to let the plane of focus fall along the middle of the depth of the chilli. Then adjust the aperture as best as you can with the aid of the DOF preview button to allow the whole chilli's depth to be encompassed in the DOF, do not use a smaller aperture than you actually need to.
 
The 24mm T&S is for landscape, getting sharpness from near to infinity at low f/numbers, or those weird model-like effects using reverse-Scheimpflug.

Why are you using 24mm for that? The chilli must be tiny in the frame from that distance and you're trying to solve a DoF problem that doesn't exist - you've got plenty of it anyway, which is presumably why you can't see any change when you tilt. Unless you're shooting from about three inches away.

The 90mm T&S is the one designed for products and table-top stuff.

Edit: I've just been looking at some of those links and I have to say they appear to make an incredibly simple principle sound complicated. Scheimpflug is a piece of cake, it takes two seconds to adjust simply by looking at the set by eye. Take the subject plane and the sensor plane, and tilt the lens so it points to where the two planes intersect. Done.

There is one thing to note though, and that is you may not have sufficient movement on the lens to get the optimum angle of tilt. Scheimpflug doesn't work so well with small format cameras, because they don't have much depth of focus and as you tilt the lens this quickly runs out, so you end up with blurred images anyway.

Small formats tend to have lots of depth of field, and not much depth of focus. Large formats are the opposite (ie 5x4in, 10x8in) with loads of depth of focus but very shallow depth of field, so that is where Scheimpflug really comes into its own. With small formats, Scheimpflug will help to maximise depth of field where you want it, but it's not a complete solution.

You could put that another way and say that generally the thing to do is forget Schempflug and just whack the lens on max tilt anyway, then raise the f/number as much as you need in order to get the amount of sharpness you want in the normal way. With the lens tilted in this manner you will be several stops better off in terms of the sharpness you get, compared to without the tilt.

For example, just looking at the set in the image posted above, I reckon Scheimpflug needs maybe 15 degrees of tilt, and I think you've only got 8 degrees on the lens?
 
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HoppyUK said:
Why are you using 24mm for that? The chilli must be tiny in the frame from that distance and you're trying to solve a DoF problem that doesn't exist - you've got plenty of it anyway, which is presumably why you can't see any change when you tilt. Unless you're shooting from about three inches away.
Click to expand...

The 24mm is the only TS lens I have and I thought it was time I put it on the camera!!

Dof issue does exist as I can not get back to front sharpness, which is what I thought this would help to achieve. I certainly haven't got plenty of dof with it.

Thanks for all your comments and taking the time to help - I will have another play now that it's light again!!
 
Sara,

It might help you to visualise the DoF region better if you replace the chilli pepper with a sheet of printed paper lying in your tent. With the angle you show the camera at, tilt up and down and you'll see the text change from only a thin strip in focus to most of the sheet.
It's also worth giving yourself a little headroom from the minimum focus distance so that it doesn't enter into the equation and confuse what you're seeing.

Bob
 
Sara,

How big is the chilli?

Do you have a converter/extender? The TSe's take an extender well and will give you a larger image.
 
Now that's a good thought! I'm sure Canon would disapprove, but a handy idea.

Another way, which I've been meaning to investigate and will mention because you've got a LensBaby Composer, is if you mount say an 80mm enlarging lens (£50 on ebay) onto the front of one of the LB optic modules, then chop the LB optics off, you might just have a very serviceable tilt lens for product photography. A medium format enlarging lens should be perfect for high quality at that range, and projects an image circle almost identical to the Canon 90mm T&S. In theory only at the moment!
 
I tried that idea Ed at the start and had to get so close to the chilli, it made my eyes water!!! I have since got a bigger chilli and am trying something else!!

Interesting ideas Richard - you trying it out first then?!!

I have to say, this TS lark is tough!!
 
swag72 said:
I tried that idea Ed at the start and had to get so close to the chilli, it made my eyes water!!! I have since got a bigger chilli and am trying something else!!
Click to expand...

Sorry Sara, I don't understand what you mean? Do you mean that you used a converter and had to get closer?

How big is the Chilli in inches?
 
Sorry Ed - Misunderstood you and brain farted at the same time!! I tried an extension tube to get in closer, boy was I close. Didn't think about the TC. Mmm, will look at that tomorrow.

The chilli is about 4 inches long.
 
swag72 said:
I tried that idea Ed at the start and had to get so close to the chilli, it made my eyes water!!! I have since got a bigger chilli and am trying something else!!

Interesting ideas Richard - you trying it out first then?!!

I have to say, this TS lark is tough!!
Click to expand...

Well I just bought the lens - Schneider 80mm f/5.6, a Componon which was the top model in its day as I recall. £15! http://www.mwclassic.com/acatalog/53222L.jpg The optics need a wipe over by the looks, but they're easy enough to take apart.

I think I can bung it in the LensBaby with BluTack just to see how it works :eek: Gotta be worth a try!
 
swag72 said:
That first diagram highlights nicely how tilting down increases the plane of sharp focus. So to achieve this the best of sharpness, where do I want to be focusing on the chilli pepper in my example?
Click to expand...

Unfortunately it's not as simple as just tilting an arbitrary angle and refocusing somewhere on the subject. Unless you calculate DOF ranges for your tilt angle nobody can tell you that precisely. Some people do precalculate spreadsheets of the DOF ranges for different tilt angles to give an idea in the field how far to be and what angle to use.

Harold Merklinger describes it in his free books available at his site and more condensed form (as articles) here.

The imo better illustration of DOF on tilted lens (taken from here):
vcdof3.gif


The clearer illustration of how DOF changes with focusing:
VCGM.gif
 
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dalex_257 said:
Unfortunately it's not as simple as just tilting an arbitrary angle...

<snip>
Click to expand...

Scheimplug is really easy. Diagrams like that only serve to confuse.

The angle to tilt the lens for maximum depth of field is as easy to see as the nose on your face. Just line it up by eye and the job is done - you have positioned the lens to deliver maximum DoF. As I said earlier.

With digital there is no need for any tables - you just keep raising the f/number and chimp it until everything you want is sharp. It's more reliable than tables anyway. Tables are theory and rely on accurate distance calculation from the photographer, but why bother with all that when you can see everything yourself, for real, by zooming in on the LCD :shrug:

The best use of knowledge is when it makes things easier, not when it makes them more difficult.
 
HoppyUK said:
Scheimplug is really easy. Diagrams like that only serve to confuse.

The angle to tilt the lens for maximum depth of field is as easy to see as the nose on your face. Just line it up by eye and the job is done - you have positioned the lens to deliver maximum DoF. As I said earlier.
Click to expand...

I wish I could agree Richard but my experience with the tilt lenses I have says otherwise. Especially for closeups and using longer lenses (I have 90mm MF tilt lens). I also think the diagrams at least serve a purpose to show what happens to DOF plane when the lens is tilted and will at least prevent some silly mistakes like tilting the other way round.
 
Here it is then, my Schneider 80mm f/5.6 LensBaby Tilt lens. Cost £15 :D And it works :) I see just this week LensBaby have announced an adapter to do something similar with Nikon lenses on 4/3rds cameras - cost $250.

IMG_3751.jpg


As mentioned above, I bought an old Schneider Componon enlarging lens off the web for £15, and BluTacked it into a LensBaby Composer mount. It works fine, but the lens is old and a bit cloudy so the image quality should crispen up a lot when I get around to cleaning it. I also need to mess about with the mount to make the most of the limited amount of focusing movement on the LB Composer.

Here's what it does. First pic is with the lens set square at f/5.6. Then with the lens tilted about 12 degrees left for optimum Scheimpflug - notice how the DoF is increased along the rule. But check the focus across the face of the box! Which goes to show that you can move the plane of sharpness to optimise its usefulness, but not make it any deeper.

f/5.6, lens set square
IMG_3741.jpg


f/5.6, lens tilted 12 degrees for optimum Scheimpflug
IMG_3744.jpg
 
I had a try at the Chilli today, took me a while to find one that was exactly 4" long (without the stem).

I used my 24L f3.5 TSe Mk2 with a 1.4x Extender giving an approx 34mm f5 T/S lens.

I set maximum shift downwards to prevent my having to tilt the camera down as much as would have been required otherwise and used the full tilt as swing to put the plane of focus between the tip of the chilli and the end of the stem.

Lit with a single flash above a lightcube.

At a registered f5 (actual f7.1) at ISO 50

Chillif5.jpg


At a registered f10 (actual f14) at ISO 200

Chillif10.jpg
 
No problem, I ate the chilli in a curry last night ;)
 
I've resurected this thread after picking up a copy of Jamie Oliver's new book, Jamie Oliver's 30 Minute Meals.

It's stuffed with tons of great pictures by David Loftus (v handy snapper :thumbs: ) and he's clearly used a tilt lens for, well, just about everything I think.

Sometimes the result is subtle, and sometimes quite striking. He uses reverse Scheimpflug and sometimes rotates the lens so that the very shallow band of sharpness runs diagonally to link key elements of the image.

You need to see the book but there's some of it here http://www.jamieoliver.com/jamies-30-minutes-meals/
 
Messing about with my DIY tilt lens (as in post #31 above). My missus hates this carpet, but I like it, and it makes a good subject for this Schempflug business. All at f/5.6, 5D2 and bounce flash.

First pic is with the lens set square, focus on the middle tin, normal DoF with sharpness fading front to rear.

Second pic is with the lens angled downwards to maximise DoF across the carpet front to rear - regular Scheimpflug adjustment.

Third pic is reverse Scheimpflug, lens angled upwards, to minimise DoF front to rear.

Fourth pic is reverse Scheimpflug and with the lens angled upwards and to the right, tilting the plane of sharpness across the image diagonally in line with the tins. This is the technique used in a lot of David Loftus' shots in the book Jamie's 30 Minute Meals, as mentioned above. The book is worth getting just for the photography - £13 Tescos.

Last pic - work this out :eek: It's a spread from the book, shot with reverse Scheimpflug applied up and left so that only the ruler is sharp. The images in the book shown are taken with left-right reverse Scheimpflug applied, which you can see clearly in the top shot.

Lens set square, normal DoF sharp across the middle, fading front and rear
IMG_4797.jpg


Max DoF - normal Scheimpflug applied, carpet sharp almost all over
IMG_4802.jpg


Minimum DoF - reverse Scheimpflug applied, narrow band of sharpness across the middle
IMG_4804.jpg


Angled minimum DoF - reverse Scheimpflug angled right, narrow DoF in line with the tins
IMG_4806.jpg


Angled minimum DoF - reverse Scheimpflug angled left, narrow DoF in line with the ruler
IMG_4819.jpg
 
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