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Forum: Pentax SLR Lens Discussion
04-09-2018, 06:20 PM
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I will apologise up front for the novel I'm about to write.
If you plan on using this for indoor use the 35 would probably be worth trying, but I must admit this isn't something I do with my panoramas, I prefer to shoot landscapes, cityscapes etc. Your 35mm will work well with indoor panos as the wider focal length will give you less focus issues that become apparent with longer focal lengths and subject matter that sits front to rear in relation to the lens. And the 35mm focal length works well with landscape panos as it will give you larger more detailed files than a single image captured at 15mm, but not that much more. It may be all you need so I'd recommend you get some test shots under your belt with the 35mm.
The 24mm and 15mm will work too, but as noted there is the potential for distortion to become an issue however the software you process images with can deal with some of this IF it has suitable lens profiles that can prepare your images before joining them as a pano. The only circumstance that I'd recommend these wider lenses for would be if you want a wide vista to cover a storm or a similarly large subject and you're limited on where you can set up. I've done a handheld pano of six images in portrait orientation using the K-1 and the D-FA 15-30 at 15mm to do this and it was still missing some parts of the storm cloud. In a circumstance like this I'd also be surprised if the Nodal Ninja wouldn't be a bit too slow to keep up with a storm so for me, the wider focal lengths can be used for panos but I don't think this is where you get the advantage of this style of photography. IMHO, YMMV etc
For outdoors I recommend you look at focal lengths from 50mm up to about 135mm, you won't need AF so you've got 50+ years of lens options to consider. So all these options in this range of focal lengths means lots of flexibility in price. Something I'll recommend here is look out for lenses that vignette and lack relative sharpness across the frame. A lens profile can probably fix the vingetting quite well but may not prevent a variation in luminance across the frame if you have a lot of something like a blue sky. For more varied subject matter this is not such an issue but it's a lens characteristic that if present needs to be known and understood for all the circumstances you're likely to use it in. No PP can fix a lens that has obvious softness on the edge of frame if it remains soft when stopped down. Typically landscape panos are shot at smaller apertures of course but if there's strong vignetting then the lens is less flexible if you want to shoot with wider apertures. I use Zeiss glass and as good as they are they also vignette at wider apertures so I have to be careful how I use them with panos.
One of my favourite lenses on APSC for panos was the DA 70mm LTD. I still use it on the K-1 but as it vignettes on the larger sensor and is a lens not designed for FF I could have sharpness issues that could mess up the pano once you start pixel peeping for printing prep. On the K3 II though it would be a good middle ground focal lenght to consider as it will give you large detailed images without the extra work that longer focal lengths require. If you want simpler still the 50mm focal length is a good point to jump up to from 35mm.
The longer focal lengths of course will give you huge images with lots of detail, but there are costs to consider. The first is the amount of frames you need to capture to get the entire scene in. So if you shoot at 100mm and a scene needs 3 rows vertically and 10 frames in portrait orientation across, that's a lot of images to combine and lots more for your computer and software to cope with. There is also the additional impact that nodal point errors will have when shooting panos with the longer focal lengths. You can obviously get this right with the pano mount so if you want the really big panos get a 100/135mm but ensure you set it up to get the most out of them otherwise you end up cropping lots and lose some of the advantage of doing a pano in the first place.
Now I once tried doing a pano with my K5 and DA*300 on my Gigapan robotic pano mount. Everything went fine once I set up the mount as best I could with such a heavy lens and I was getting an amazing amount of detail of this bridge when I got to the end of the SD card capacity with about 3/4 of the images needed to make the pano work. I had no real need for such a detailed pano, I just wanted to try it out to see what it would get me and I processed what I had and really wished that I had the bits that were missing because it was awesome. In the end I put hundreds of unnecessary shutter actuations on my camera for nothing as not only did I not get the last quarter of the bridge but I ended up missing the necessary top parts of the bridge as I couldn't get near the correct nodal point with such a large lens. The solution is to go for a shorter tele as suggested to get lots of detail without the drama or add lots of overlapping frames at the top, bottom and both sides of your subject.
If you want a recommendation beyond this I'd suggest you consider how close you will be to some elements of your subject. For example with a pano the composition rules for wide angles is a good way to start off where you have a brilliant scene and can combine it with a strong anchoring element in the foreground. If the foreground subject is a fair bit closer to you than the background and you still want the background to be in focus as well, the wider field of view options will make this a simpler process where you could stop down, work the hyperfocal focus point and probably get everything you want in the one pass. So something like your 35mm or maybe a 50mm will give you better scope in achieving this. If you went with a longer option you're going to need to shoot the foreground frames at one focal point and the background with another. And focus stacking with a single frame is not that uncommon but to do this with a pano is that much more complex to get right. And to do this you would do a sweep focused on your background then when you get to the foreground you would need to take two or more frames to ensure the foreground the middle distance and distant elements are all captured in focus with exactly the same frame. Note that some lenses will produce variations in the frame as you change the focal point from near to infinity which adds more work to do in PP, especially if parts of the foreground subject are in multiple frames. If you're okay with working in Layers then none of this is insurmountable and it will give you some spectacular shots. My recommendation for those sorts of subjects is to ensure the foreground is sharp as a tack and use the hyperfocal distance for the rest if the scene will allow it. This simplifies the workflow especially if you can isolate your foreground subject without unnecessary overlapping frames.
TL;DR? My recommendations in summary would be: Consider focal lengths between 50mm and 135mm, don't be too worried about AF as panos are best shot with everything in manual including focus. If you have the funds or can find some good second hand manual options pick up a 50mm and something in the range between 50mm and 100mm. Then if you really want large detailed images something around the 100-135mm range. If you can only afford a single lens look around the 50-80mm as providing the most flexible options.
Tas
NOTE: Overlap your photos by at least one third, the outside overlap to the top, bottom sides etc can be reduced if you rotate the lens around the entrance pupil, the details on this can be found here: http://www.johnhpanos.com/epcalib.htm |
