Pages: [1]   Go Down

Author Topic: D700+ PC-E stitching question  (Read 4876 times)

kuau

  • Full Member
  • ***
  • Offline Offline
  • Posts: 212
D700+ PC-E stitching question
« on: July 08, 2009, 01:42:38 pm »

I jsut got my D700, 24,45,and 85mm PC-E lenses very excited.
Question when doiing stiches.
When doing a landscape image, do I need to do 2 or 3 exposures. Meaning one taken center, then one to the left and one to the right on the shifting of the lens?
Then the same question when doing a Vertical shot, 2 or 3 exposures?
I realize on the 24mm lens If I do a extreme shift to the left or right image quality goes down, not sharp on the corners.

Thanks
Steven
Logged
__________________________________________________________________________
Leica S006, Leica SL HP Z3200 PS Printer
http://www.kuau.com

JeffKohn

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1668
    • http://jeffk-photo.typepad.com
D700+ PC-E stitching question
« Reply #1 on: July 08, 2009, 03:07:19 pm »

Probably best to go ahead and take 3 images if you're using full shift, so that you've got plenty of overlap for stitching, especially if you're not shifting the camera in the opposite direction as the lens to avoid parallax.  Also, I know Photoshop's stitcher needs more than a few mm overlap to work. If I tried to take two horizontal images on a DX sensor  with full horizontal shift, Photoshop would say it couldn't stitch the photos even though they should have had 3-4mm of overlap. This may be less of an issue if stitching manually, but even so having extra overlap can be useful in case you need to use masking to fix any problem areas along the seam.

To clarify, I'm assuming you are shifting on the 'short' axis of the sensor. If you are shifting on the long axis of the sensor (eg horizontal shots and horizontal shift), then two images should have plenty of overlap.
« Last Edit: July 08, 2009, 03:09:16 pm by JeffKohn »
Logged
Jeff Kohn
[url=http://ww

kuau

  • Full Member
  • ***
  • Offline Offline
  • Posts: 212
D700+ PC-E stitching question
« Reply #2 on: July 08, 2009, 04:45:55 pm »

Quote from: JeffKohn
Probably best to go ahead and take 3 images if you're using full shift, so that you've got plenty of overlap for stitching, especially if you're not shifting the camera in the opposite direction as the lens to avoid parallax.  Also, I know Photoshop's stitcher needs more than a few mm overlap to work. If I tried to take two horizontal images on a DX sensor  with full horizontal shift, Photoshop would say it couldn't stitch the photos even though they should have had 3-4mm of overlap. This may be less of an issue if stitching manually, but even so having extra overlap can be useful in case you need to use masking to fix any problem areas along the seam.

To clarify, I'm assuming you are shifting on the 'short' axis of the sensor. If you are shifting on the long axis of the sensor (eg horizontal shots and horizontal shift), then two images should have plenty of overlap.

Yes, I am not moving the camera at all just the shift on the PC-E Lens.
Though I am a little confused when you say shifting on the short axis of the sensor.
example. I am taking a landscape/horizontal image My options are to either shoot one exposure shifted left, then right, or do left, center, then right.
examlpe 2: I am taking a portrait/verticle image, I have rotated the PC-E lens so I can shift left to right, not up and down. 2 or 3 exposures?
Logged
__________________________________________________________________________
Leica S006, Leica SL HP Z3200 PS Printer
http://www.kuau.com

Mort54

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 590
    • http://
D700+ PC-E stitching question
« Reply #3 on: July 08, 2009, 05:22:11 pm »

Hi Steven.

If your camera is oriented vertically, and you shift the maximum amount (11.5mm) both left and right, you'll only have a small sliver of overlap between two images. That sliver of overlap probably won't be enough to keep the stiching software happy, so you probably need to also do a center shot (three shots total). Likewise if your camera is in landscape orientation and you shift the maximum up and down, you'll need to do three shots. If you shift less than the maximum amount (maybe only 8 or 9 mm), then you can probably get by with two shots.

If you are in landscape mode, and shifting left and right, or in vertical orientation, and shifting up and down, then you can get by with only two shots, since even at maximum shift, you still have considerable overlap between two shots.

A few additional things to keep in mind:

First, shoot in manual exposure mode when shifting. The AE meter is badly fooled when the lens is shifted. If you rely on auto-exposure, shifted images come out extremely dark. This is a metering issue, not the result of how much light hits the sensor when shifted. For example, the manual exposure you use when shooting an unshifted image, is also the correct exposure to use for the shifted case.

Second, if you are oriented in landscape mode, and want to create a panorama by shifting left and right, be advised that you'll get pretty bad vignetting if you shift more than 8mm. If you are in landscape mode and shift up and down (or in vertical orientation and shifting left and right), you can safely shift by the max amount without any vignetting.

Third, if you have close foreground elements, you'll get parallax effects if you shift without moving the body. In other words, if you have close foreground elements, you need to keep the front lens element positioned in the same location while you shift the body. Since the lens doesn't have it's own tripod foot, you'll have to first shift the lens, and then slide the body in it's tripod mount by the same amount in the opposite direction. Hope this last part makes sense. If not, let me know and I'll try to be a little more clear.

I have the 24 PC-E, and it's an excellent lens. I use if mostly for shifts, very seldom for tilts (even tho I'm a landscape shooter). There are some real downsides to tilting that I've never seen mentioned in discussions of tilt-shit lenses, but I've already babbled on long enough.
Logged
I Reject Your Reality And Substitute My

Rob C

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 24074
D700+ PC-E stitching question
« Reply #4 on: July 09, 2009, 08:21:53 am »

Quote from: Mort54
There are some real downsides to tilting that I've never seen mentioned in discussions of tilt-shit lenses, but I've already babbled on long enough.




Would you like to amplify on that, if you have time and patience? A little informed babble never did anyone any harm!

Rob C

kuau

  • Full Member
  • ***
  • Offline Offline
  • Posts: 212
D700+ PC-E stitching question
« Reply #5 on: July 09, 2009, 09:32:29 am »

Mort,
Thanks for the explanation makes perfect sense to me.
So for my needs it sounds like to me the only time I need to do 3 shots is when the camera is vertical and I am shifting maximum left to right, not up and down correct and if the camera is in landscape position and I am shifting left to right only 2 shots required.

To avoid parallax effect, I need to shift the camera opposite to what the lens is doing? Do I need to invest in RRS pan equipment? If I shift the lens 8 degrees to the left I need to shift the camera 8 degrees to the right? I assume I need to be precise? I can now see the advantage of using a med format tech view camera and a phase one back where I can move the back and not the lens.

When using my 24mm PC-E lens I don't think I will use tilts either, just shoot at f11 or maybe F16 or do you not recommend shooting at F16??
Though when shooting with my 45mm or 85mm I may use some tilt to increase dof  any thoughts on this?

Steven




Quote from: Mort54
Hi Steven.

If your camera is oriented vertically, and you shift the maximum amount (11.5mm) both left and right, you'll only have a small sliver of overlap between two images. That sliver of overlap probably won't be enough to keep the stiching software happy, so you probably need to also do a center shot (three shots total). Likewise if your camera is in landscape orientation and you shift the maximum up and down, you'll need to do three shots. If you shift less than the maximum amount (maybe only 8 or 9 mm), then you can probably get by with two shots.

If you are in landscape mode, and shifting left and right, or in vertical orientation, and shifting up and down, then you can get by with only two shots, since even at maximum shift, you still have considerable overlap between two shots.

A few additional things to keep in mind:

First, shoot in manual exposure mode when shifting. The AE meter is badly fooled when the lens is shifted. If you rely on auto-exposure, shifted images come out extremely dark. This is a metering issue, not the result of how much light hits the sensor when shifted. For example, the manual exposure you use when shooting an unshifted image, is also the correct exposure to use for the shifted case.

Second, if you are oriented in landscape mode, and want to create a panorama by shifting left and right, be advised that you'll get pretty bad vignetting if you shift more than 8mm. If you are in landscape mode and shift up and down (or in vertical orientation and shifting left and right), you can safely shift by the max amount without any vignetting.

Third, if you have close foreground elements, you'll get parallax effects if you shift without moving the body. In other words, if you have close foreground elements, you need to keep the front lens element positioned in the same location while you shift the body. Since the lens doesn't have it's own tripod foot, you'll have to first shift the lens, and then slide the body in it's tripod mount by the same amount in the opposite direction. Hope this last part makes sense. If not, let me know and I'll try to be a little more clear.

I have the 24 PC-E, and it's an excellent lens. I use if mostly for shifts, very seldom for tilts (even tho I'm a landscape shooter). There are some real downsides to tilting that I've never seen mentioned in discussions of tilt-shit lenses, but I've already babbled on long enough.
Logged
__________________________________________________________________________
Leica S006, Leica SL HP Z3200 PS Printer
http://www.kuau.com

kers

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 3707
    • Pieter Kers
D700+ PC-E stitching question
« Reply #6 on: July 09, 2009, 10:48:40 am »

Quote from: kuau
To avoid parallax effect, I need to shift the camera opposite to what the lens is doing? Do I need to invest in RRS pan equipment? If I shift the lens 8 degrees to the left I need to shift the camera 8 degrees to the right? I assume I need to be precise? I can now see the advantage of using a med format tech view camera and a phase one back where I can move the back and not the lens.

When using my 24mm PC-E lens I don't think I will use tilts either, just shoot at f11 or maybe F16 or do you not recommend shooting at F16??
Though when shooting with my 45mm or 85mm I may use some tilt to increase dof any thoughts on this?

Steven
Steven


Hello Steven, at d16 you loose more of its brillance- so use d8 for the 85mm - d11 for  24mm and for 45mm  when using complete shift

Wthout shift use d5,6- 8 for best results- unless you need the extra DOF

Just stiching with Photoshop on automatic works good !  The parallax error is only a problem at short distances- you do not need RR stuff ( - But i have it for panorama's)

You can buy a simple sliding plate from manfrotto- 40 $ I Guess-  

Pieter
Logged

kuau

  • Full Member
  • ***
  • Offline Offline
  • Posts: 212
D700+ PC-E stitching question
« Reply #7 on: July 09, 2009, 11:07:48 am »

Thanks Pieter
So for landscape stuff parallax is really not an issue? More of an issue if I was doing closeup / macro work and doing shifts?
Steven


Quote from: kers
Hello Steven, at d16 you loose more of its brillance- so use d8 for the 85mm - d11 for  24mm and for 45mm  when using complete shift

Wthout shift use d5,6- 8 for best results- unless you need the extra DOF

Just stiching with Photoshop on automatic works good !  The parallax error is only a problem at short distances- you do not need RR stuff ( - But i have it for panorama's)

You can buy a simple sliding plate from manfrotto- 40 $ I Guess-  

Pieter
Logged
__________________________________________________________________________
Leica S006, Leica SL HP Z3200 PS Printer
http://www.kuau.com

Mort54

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 590
    • http://
D700+ PC-E stitching question
« Reply #8 on: July 09, 2009, 12:23:42 pm »

Quote from: Rob C
Would you like to amplify on that, if you have time and patience? A little informed babble never did anyone any harm!
Hi Rob. What caught me by surprise is how narrow the DOF is on either side of the tilted focus plane. In my testing, the DOF seemed much narrower than the chosen aperture would suggest, or that I'm used to without tilts. [Edit: See JeffKohn's comments further down in this thread, indicating DOF should be the same for a given aperture, only tilted. I don't have any background in optics to say Jeff is wrong, and in fact, that was my assumption going in, before I got the lens. However, based on my limited testing, that doesn't seem to be what I'm seeing. I seem to be seeing a much narrower DOF for a given aperture when the lens is tilted. I can't explain why that would be the case. I guess I need to do some more testing.]

This sounds contradictory, I know. The tilted focus plane makes it easy to get near and far objects in focus, even at large apertures, which makes it appear that you have great DOF. And you do, but only as long as these near and far objects are relatively close to the tilted focus plane. Anything near the camera that rises above or below the focus plane goes fuzzy pretty quickly. Maybe everybody knows this about tilts, but it caught me by surprise.

For example, if you have a neaby tree that extends above the tilted focus plane by even a relatively small distance, the top of the tree will be very blurry, even with relatively small apertures (based on a test shot I did with a roughly 25 ft tall tree maybe 50 ft from the camera). This may not be a problem for some, but for me, living in the mid-west, it's often the case that I have taller objects in the foreground, and it's very disconcerting to have this seemingly sharp focus extending from near to far, yet have these nearby treetops be fuzzy out-of-focus blobs. It's not natural looking, and immediately draws the eye.

A tilted focus plane can work wonders if the landscape has a relatively flat foreground (or at least no tallish foreground objects). In that case, with no foreground objects extending outside the focus plane, you won't notice this narror DOF.

Hope this makes sense,
Mort.
« Last Edit: July 09, 2009, 01:25:41 pm by Mort54 »
Logged
I Reject Your Reality And Substitute My

Mort54

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 590
    • http://
D700+ PC-E stitching question
« Reply #9 on: July 09, 2009, 12:41:28 pm »

Quote from: kuau
So for landscape stuff parallax is really not an issue? More of an issue if I was doing closeup / macro work and doing shifts?
Steven, it depends on what kind of landscapes you shoot. Many people like to have prominent near, middle and far elements in the composition. Think David Muench type compositions, with very dramatic nearby foreground objects. You WILL see parallax effects in those kinds of landscapes if you just shift the lens without compensating the movement at the body. If your landscape style is more middle and far, with no nearby foreground elements, then you can safely ignore parallax effects.
Logged
I Reject Your Reality And Substitute My

JeffKohn

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1668
    • http://jeffk-photo.typepad.com
D700+ PC-E stitching question
« Reply #10 on: July 09, 2009, 12:44:01 pm »

Tilt neither increase or decreases the DOF, only changes its orientation; but you're correct that it's no panacea. I agree it is pretty rare that you'll have a composition where the desired plane of focus is flat enough to allow a wide shooting aperture (for landscapes anyway). It's still often necessary to stop down, and some compositions will definitely be problematic. But that doesn't mean it can't be useful.

With the 24 PC-E in particular, you've already got a decent amount of DOF, and just a degree or two of tilt can sometimes make the difference in getting the foregound really sharp without distant objects going too soft (or allow me to shoot at f/8 instead of f/16). It's easy to over-estimate the amount of tilt needed though, I made that mistake a lot when I first started using this lens but now I use the charts from the LL article a while back to estimate the amount of tilt needed.
Logged
Jeff Kohn
[url=http://ww

JeffKohn

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1668
    • http://jeffk-photo.typepad.com
D700+ PC-E stitching question
« Reply #11 on: July 09, 2009, 12:50:46 pm »

Quote
To avoid parallax effect, I need to shift the camera opposite to what the lens is doing? Do I need to invest in RRS pan equipment? If I shift the lens 8 degrees to the left I need to shift the camera 8 degrees to the right? I assume I need to be precise? I can now see the advantage of using a med format tech view camera and a phase one back where I can move the back and not the lens.
You shift the lens in millimeters, not degrees. Do not pan the camera when shift-stitching. Instead, you just need to move the camera in the opposite direction as the lens shift, by the same number of millimeters. You don't need any special equipment to do this on the horizontal axis, as long you're already using a QR clamp that allows you to move the camera left/right within the clamp. The closer to exact you can get, the better; but even if you're off by a mm or two that will still be better than if you had not shifted the camera at all.

When using vertical shift, there's really no way to shift the camera up/down without using special equipment. But I've found that parallax usually isn't a problem for vertical shift-stitches as long as there's plenty of overlap between the frames, and it's not something I do all that often.
Logged
Jeff Kohn
[url=http://ww

Mort54

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 590
    • http://
D700+ PC-E stitching question
« Reply #12 on: July 09, 2009, 12:51:10 pm »

Quote from: kuau
When using my 24mm PC-E lens I don't think I will use tilts either, just shoot at f11 or maybe F16 or do you not recommend shooting at F16??
Hi Steve. By your sig it looks like you are shooting with a 24-MP A900. With that camera you'll be resolving lens diffraction effects at f/16 (loss of sharpness and contrast). If the composition allows it, use larger apertures, and tilts if you can. On the other hand, if the composition needs the depth of field, and you have nearby foreground elements that make tilts a problem, then I'd go ahead and stop the lens down. Yes, you're going to loose some sharpness and contrast due to diffraction, but not as much as you loose as a result of having too narrorw a DOF.
Logged
I Reject Your Reality And Substitute My

Mort54

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 590
    • http://
D700+ PC-E stitching question
« Reply #13 on: July 09, 2009, 12:56:54 pm »

Quote from: JeffKohn
Tilt neither increase or decreases the DOF, only changes its orientation
That was my assumption going in, but for some reason it doesn't match what I'm seeing. Not sure why. Based on my informal testing (just shooting images and looking at the results), even stopping down to f/16 left nearby treetops fuzzy blobs, while the trunks close to the focus plane were nice and sharp. No wind, and the results are very repeatable. At 24mm, I would have expected something extending maybe 15 ft above the focus plane, at a distance from the camera of roughly 50 ft, to be relatively sharp. That's not what I'm seeing.
« Last Edit: July 09, 2009, 01:11:35 pm by Mort54 »
Logged
I Reject Your Reality And Substitute My

JeffKohn

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1668
    • http://jeffk-photo.typepad.com
D700+ PC-E stitching question
« Reply #14 on: July 09, 2009, 02:55:35 pm »

Quote from: Mort54
That was my assumption going in, but for some reason it doesn't match what I'm seeing. Not sure why. Based on my informal testing (just shooting images and looking at the results), even stopping down to f/16 left nearby treetops fuzzy blobs, while the trunks close to the focus plane were nice and sharp. No wind, and the results are very repeatable. At 24mm, I would have expected something extending maybe 15 ft above the focus plane, at a distance from the camera of roughly 50 ft, to be relatively sharp. That's not what I'm seeing.
I got some results like this early on, and it was because of using too much tilt. Check out the article and charts in here. On my D300, once I started using those charts to determine tilt I almost never used more than 1-1.5 degrees. For full-frame you might be a little closer to your foreground due to the different FOV, so a bit more tilt might be necessary. But if you're getting 'fuzzy' distant objects at the top of the frame it's probably because of too much tilt or mis-focusing.

Another possibility could be if you're using tilt and shift at the same time, such that you're using the extreme edges of the lens' imaging circle. I found that even on DX sensors using the full 11mm of shift with the PC-E would result in substantial loss of image quality at the far edges and corners.
« Last Edit: July 09, 2009, 02:57:01 pm by JeffKohn »
Logged
Jeff Kohn
[url=http://ww

button

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 427
    • http://
D700+ PC-E stitching question
« Reply #15 on: July 09, 2009, 03:52:20 pm »

I've played around with tilting for mosaic stitching purposes, and I've found that tilting works most effectively for the foreground, where DOF is most limited by near focus.  For example, let's say you are shooting a landscape, and you want to make a 4 shot mosaic.  Tilt your lens for the foreground 2 shots (the bottom 2), and then either limit or remove the tilt for the more distant part of the image (the top two shots).  

The trick is learning how to do this stuff quickly before the light changes too much- I'd say if you can make a 4 shot mosaic with 3 bracketed exposures per station in 5 minutes or less, you're doing pretty well.  Success requires planning and practice, no question about it.

John
Logged

kuau

  • Full Member
  • ***
  • Offline Offline
  • Posts: 212
D700+ PC-E stitching question
« Reply #16 on: July 09, 2009, 04:44:06 pm »

Hey everyone, thanks for all the replies, I think I am starting to understand what I need to watch out for when using my PC-E lenses.
To summarize let me see if I got this now.
When doing a vertical shot and I want to do a horizontal shift, I should do 3 exposures left center and right
When doing a horizontal shot with a horizontal shift then all I need is 2 exposure left and right
Because I am using a D700 I have to rotate the lens 180 degrees so I can't see the shift scale, so I will usually do full shifts and then crop out any weird stuff on the edges in PS.

If doing landscapes while doing shifts if there is an object that is in the foreground I need to correct for parallax by shifting the camera opposite of the shift of the lens. I don't need to be precise but get it close. So full shift right on the lens  = full shift left of the camera body.

I did read the article about focusing PC-E lenses. They show an example of 3 images 1 focus foreground, 1 focus background and 1 with tilt, but it does not say where the focus was at on the tilt? My question is if most of my landscape's are far away and usually focus infinity, on the PC-E 24mm lens would I keep the focus at infinity and do a 1 degree tilt to bring the foreground in focus? Or once again since the 24mm has good dof anyways at F8-11 don't even bother with a tilt?

Wow, lots to learn.

Steven
Logged
__________________________________________________________________________
Leica S006, Leica SL HP Z3200 PS Printer
http://www.kuau.com

Mort54

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 590
    • http://
D700+ PC-E stitching question
« Reply #17 on: July 09, 2009, 05:19:41 pm »

Quote from: JeffKohn
I got some results like this early on, and it was because of using too much tilt. Check out the article and charts in here.
Thanks Jeff, I'll give this a read. A quick look at the tables has already confused me, however. The tables seem to be saying that the more horizontal my focus plane is, the less tilt I should use, i.e. the closer to horizontal the focus plane gets, the longer the perpendicular distance from the focus plane to the lens, and the less tilt should be used. That sounds counterintuitive. What am I misunderstanding?

Mort.
Logged
I Reject Your Reality And Substitute My

JeffKohn

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1668
    • http://jeffk-photo.typepad.com
D700+ PC-E stitching question
« Reply #18 on: July 21, 2009, 12:28:47 pm »

Quote from: Mort54
Thanks Jeff, I'll give this a read. A quick look at the tables has already confused me, however. The tables seem to be saying that the more horizontal my focus plane is, the less tilt I should use, i.e. the closer to horizontal the focus plane gets, the longer the perpendicular distance from the focus plane to the lens, and the less tilt should be used. That sounds counterintuitive. What am I misunderstanding?
Sorry for losing track of this thread, I've been on vacation. I agree the article is not precisely clear on which distance you should be measuring to use with the charts. I've been using the distance from the camera to my foreground subject and it seems to work resonably well. Unless you have a need to shoot with wide aperture (I'm usually in the f/8-f/11 range), it's probably better to err on the side of not enough tilt rather than too much, since you're probably still going to be covered by DOF if you use a little less tilt, whereas if you use too much tilt the top of the frame will go soft.
Logged
Jeff Kohn
[url=http://ww
Pages: [1]   Go Up