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Use of an External Monitor for Tilt/Shift Stills: Small HD DP6 - By Michael Kunitani

 

Introduction:

Why use an accessory field monitor? These 4 to 7 inch monitors were developed for DSLR video use, not stills. However, for Tilt/shift use the field monitor at full image view facilitates composition at awkward viewing angles and at magnified view, can aid in fine adjustment of tilt and focus. This article covers how a high resolution external monitor can be uniquely useful in low angle T/S photography and reviews the Small HD DP6 in specific.

One of the more dramatic landscape uses of tilt/shift lenses is to mount the camera to be quite low to the desired focal plane, usually the ground. Lens tilt allows everything on this ground plane to be in focus, from a few inches to infinity. The lens center distance to the ground plane is dependent upon the lens focal length and lens design, but typically max downward tilt results in a lens distance of about 7 inches for a 24mm Tilt/Shift lens. For a camera in portrait/landscape orientation the bottom of the camera body will be only 4"-5" from the ground. Tripods with center columns typically cannot mount the camera this low. One solution is a tripod with a center column which rotates to horizontal (or downward), splay the legs and set the back leg up a bit higher to lower the camera even more.

 


 

 

Consideration of resolution:

The resolution (HD) of the DP6 monitor is 1280 X 800. It is currently is the highest available for a 5.6" monitor as of this writing, and will soon have competition from Marshall, Ikan and others, but like the DP6 they will not be cheap. I have owned other 480 X 800 monitors, like the 7" Lilliput, and it seemed rather soft by comparison. It's really hard to tell precisely where the optimum lens focus is. If you are going to use the monitor primarily for composition, perhaps high resolution may not a big deal, but for my application of fine tuning lens tilt and focus, a high resolution monitor makes a very noticeable improvement. I wasn't interested in an EVF as it would not allow critical viewing from 1-2 ft. distance, a necessity with the low angle T/S application.

Tilt lens movement is carefully optimized for a chosen foreground and background targets that lie on the desired focal plane. The magnified (5-10X) Live View LCD is used with the joystick to isolate foreground and background targets for critical adjustment. The target areas are rechecked after focus, as the tilt and focus parameters interact. Several iterations of knob twisting for both tilt amount and focus are usually needed. The lower the camera is to the focal plane, the greater the tilt angle and the more sensitive the tilt adjustments become. Like any difficult manual focus adjustment, a higher resolution LCD view provides greater adjustment accuracy. For very low angle shots I always use some shift as well to square up the perspective distortion. Again Live View is the principle tool in dialing in the amount of shift. Recomposing is always necessary after a significant shift adjustment.

If Canon would provide a swiveling, high resolution LCD on its full frame DSLRs, this article would not be necessary, as the 1.0 MDot LCD on of its recent cameras already have sufficient resolution. However with low angle tilt/shift use, the LCD on the camera back is simply is too low for practical viewing, requiring a photographer to lie on their belly to view the LCD while the tilt adjustment requires two hands: one to turn the tilt (or shift) lock knob and the other the tilt (or shift) adjustment knob. An external monitor allows the photographer to squat behind the camera and view the much larger LCD display from above, while the larger screen size allows adequate visual resolution while the monitor is at arm's length.

 

 

Hardware & Software Features:

As mentioned above, this field monitor was originally developed for DSLR video application. What makes the DP6 a field monitor is that they are battery powered, and monitors have mounts to use camera batteries from many popular DSLR video cameras, so you can use the same battery as your camera. On a freshly charged OEM version of Canon LPE6 the DP6 runs for about 1.5 hour of use with one battery. Two batteries can be mounted at once. A small swiveling ball head with a cold shoe mount allows use of the camera's flash shoe for mounting the monitor, which also has threads to accept the ball head in any of the 4 edges of the monitor. The Small HD shade hood is the deepest of any I have seen: it's a 7" deep black neoprene sleeve held in place with 4 plastic rods that plug into the corners of the monitor. Finally a mini HDMI cable connects the camera body to the DP6, which accepts a standard HDMI plug. While this is a very common DSLR hookup, the mini HDMI plug does not have a very sturdy connection at the camera end, and at Small HD has a mini HDMI supporting clip to prevent this plug from working loose. They need a mini HDMI plug support that can be used with an Arca Swiss style L plate from RRS or Kirk.

One may think that software features such as focus peaking, a very common in video field monitors, would help to achieve maximum sharpness with a MF lens, but I have not found this to always be the case. In focus peaking, the high frequency (sharpest) edges are highlighted in white. Therefore these edge pixels are unavailable for displaying contrast that one uses to assess maximum focus. I found that the peaking feature can quickly identify which objects are close to being in focus, but nothing beats manual focus with a higher resolution screen for the most accurate, optimally sharp focus. The Small HD products have Focus Assist + feature, which darkens the image and further amplifies the visibility of the white edged focus peaking effect. This focus peaking on steroids makes it really easy to identify DOF, which area of the frame is in focus. However, there is some additional sacrifice of display resolution with this exaggerated peaking boost. I would judge focus assist + to be most useful when quick (not necessarily the most accurate) focus adjustments are a priority, such as video tracking a moving subject with a MF (focus follow). While I do turn focus peaking on/off I do not use focus assist+.

Another great feature is the DP6 scaling presets for Nikon & Canon, "DSLR auto scaling", which allow auto scaling of the display so that nearly all of the monitor pixels are used. It can also be custom set for other camera brands. This can be quite a problem with many field monitors as much of the monitor's screen is wasted on unused black border during scaling. I set the DP6 to "C DSLR Rec", in which the Canon Live View image uses the entire the DP6 screen.
Watch the Small DP video on "effective Pixels" that explains this confusing issue.

 

 

 

The 1:1 pixel mapping feature creates a DP6 display pixel to pixel equivalent to the native HD output of the camera, or about 2/3 the image size of the Canon 5D Mark II LCD. Using the 1:1 on the DP6, Live View 5-10X magnification and the joystick on the camera, one can move about in the frame, with monitor resolution matching the camera HDMI output. The sensation is much like using a loupe on the ground glass back of a 4x5 view camera, except the image is not backwards/upside down. If you want to see the entire image for composition, the monitor has to resize the image to fit the aspect ratio of the monitor, and the rescaling will result in a small loss of resolution. However 1:1 pixel mapping preserves the maximum resolution provided by the HDMI camera output and does not try to display the entire image. To maximize LCD resolution, scroll through the LCD options by pressing Info button on the back of the camera several times. One of the views has the image filling the camera LCD with no exposure, camera parameters nor histograms. On the DP6 the horizontal pixels match those of the camera LCD and just a few % of the top and bottom of the image are missing; very little. Now activate the 1:1 feature and in the DP6 one loses approximately 10+% of the view from each edge. However in this setup the cut off areas of the image are viewable via scrolling the camera magnified area. The resulting DP6 image fills the screen and is really sharp, as the camera HDMI output clearly has the greatest resolution in this mode, and that enhanced resolution is being faithfully presented on the DP6 1:1 display feature. 1:1 pixel mapping along with 5X magnification is highly recommended for fine adjustment of focus or tilt angle after the composition is set.

The DP6 allows some customization of the relatively few control buttons. I have the outer, large button on the top right set to peaking (on/off) and the smaller button next to it on the top right set to 1:1 (on/off). The power button is on the side and would appear to minimize accidental actuation. The thumb wheel on the top right walks through the menus, while pressing the wheel down selects the choice.

Setting up the DP6 takes a few minutes and increases the working bulk of the camera so I use it selectively. The DP6 is plenty bright, I usually don't use the shade and I don't crank up the brightness beyond 50. Too much brightness seems to degrade the fine resolution. Like all LCDs, glare can be a problem in certain situations, and then it takes a minute to attach the shade. From time to time Small HD has sales of "B stock" which are units with several dead pixels. I got one with a $300 discount. I only see the dead pixels when using "focus assist +", which is a form of highly amplified focus peaking. Get on their mailing list if you want to be notified of B stock sales.

 

Examples/Use:

In the following petroglyph photo the tripod is set up as shown in the introduction, and the rear legs of the tripod are within an few inches of a 10 foot vertical cliff. I could not get behind the camera, so there is no way I could adequately view the camera LCD and adjust the lens movements without an external monitor like the DP6.

 

 

On this Bandon Beach shot, the sky was a featureless blue; I figured the beach itself would have to provide some additional drama. I found a small seepage flow near the cliff base creating patterns in the sand. Using the tripod set up described above, the tripod legs stood in the flowing water with the 24 tilt shift lens within a few inches over the water surface.

 

 

This set up has worked really well when the tripod sits in shallow water as these flat, near field scenes lend themselves to T/S photography.

 

 

 

Here is another application where an external monitor can help with low angle T/S composition. Using the same low angle set up with the monitor pointing upwards, I fine adjust the tilt/shift and focus in a safer, dry portion of the beach. With the camera on Live View and the DP6 1:1 feature off, I chase the waves out as they recede, and set down the tripod facing the sunset and ocean. Only a few seconds are available to compose, shoot off an image or two, grab the tripod and scurry back to dry land just ahead of the next oncoming wave.

 

 

Michael Kunitani (Mike K) is a regular FM Forum contributer. If you have any questions or feedback, checkout his forum profile.

Mike K has been a digital photography enthusiast since 2000 and an early participant of the FM forums, when simple login names were still available. As a photographer his passion has always been for landscapes containing an element of drama. To help create a more dramatic point of view, he recently has found renewed inspiration using the high quality Canon 17 and 24mm tilt/shift lenses. Being a scientist by academic training, Mike doesn't mind the extra technical challenge of the tilt/shift lens movements. This article grew out of his search for a better tool set for capturing this artistic vision.