Dann-Oh 40 Posted November 10, 2022 Hey all, I have been following along on Becky Kagan Schott's photogrammetry journey of the Cornelia B Windiate via Instagram. I am wondering if anyone here can help answer some basic questions. How small of a boat is considered too small? I am interested in trying to make a project out of the boat "midnight hour" which was a squid fishing boat that got greedy and tried to haul in more than it could support and capsized and sank. I think this is a super cool and unique idea but I have no idea where to start. Share this post Link to post Share on other sites
TmxDiver 41 Posted November 11, 2022 Hi, I actually haven't dove the Midnight Hour (yet). Not sure why other than it is shallow and I tend to dive the deeper wrecks. However, I did see a video on-line and there is one thing that I noticed that could make your task hard: kelp on the wreck that is moving. I'm facing this issue right now as I work on a model of the entire Yukon wreck. I'm not sure if that is a seasonal thing or permanent. But, kelp moving around will complicate building a model. It is definitely not too small for model. I've build models of much smaller. For example, there is a Piper airplane on the front side of Catalina that I did early in my photogrammetry: https://wreckedinmyrevo.com/2020/12/21/piper-warrior-photogrammetry-model-130-feet-catalina-island/ I recently posted a presentation of some photogrammetry basics that might be of some use: https://wreckedinmyrevo.com/2022/10/12/presentation-photogrammetry-a-primer/ Most of my photogrammetry information, models, etc is at: https://wreckedinmyrevo.com/category/photogrammetry/ There are some challenges with the environment here is SoCal (dark, particulate matter, etc.) that will complicate things in general but if you are patient, you will figure it out. Also, you can always start by building a model of "part" of a wreck. I did that with the Yukon guns and prop as I was learning. Good luck, - brett 1 Share this post Link to post Share on other sites
TmxDiver 41 Posted November 11, 2022 PS - I would also recommend practicing on land before you get in the water. Share this post Link to post Share on other sites
Dann-Oh 40 Posted November 11, 2022 (edited) Brett, I was on your site this afternoon looking around with hoping to find an example of your workflow. I'm just worried it might be tough for me at my current skill set (OC Air Recreational limits). I worry about bottom time and the need for multiple dives as I don't know anyone with a boat to get out to the Midnight Hour, or any site regularly for that matter. I think starting out with a portion of the boat would be a good starting point. What would you recommend for lens choice? I'm using micro3/4 and have access to 8mmf3.5 fisheye, 14-42mm f3.5-5.6 , 30mm f3.5 macro, 60mm f2.8 macro. Edited November 11, 2022 by Dann-Oh Share this post Link to post Share on other sites
TmxDiver 41 Posted November 11, 2022 Hi, If you send me a DM with your contact info (email and mobile), I can try giving you a call at some point tomorrow. It might be easier to discuss live. A few comments based on your post: 1) I would not try to do a multi-dive project to begin with. Pick something simple that you can do in one dive. Even if it is just a portion of a wreck. 2) Yes - getting out to the Midnight Hour might not be easy and you might want to dive your target and think about how you would make a model before you do the dive to make the model. Have you thought about doing a feature or small section on the Yukon? Boats go there every week and the top of the wreck is at about 65 fsw and the sand about 105 fsw. 3) For lenses, I personally prefer wide angle rectilinear but generally shoot with either the WWL-C or WWL-1B. You can toss out the macro lenses for anything to do with photogrammetry. That being said, there are a few things to keep in mind: 3a) Metashape will do lens corrections so if you use a fisheye, it will compensate (to a certain degree) for the barrel distortion. I'm not sure if there is lens correction profile for the 8mm f3.5 fisheye you have and I don't even really know if there is a canonical database of what Metashape does have profiles for. 3b) With the usual conditions in California, the reason it helps to have a wide angle or fisheye is that you can get closer to your target and illuminate it better and still get a decent amount of "coverage" in each photo. You will typically need about a 50-70% overlap of the photos for the alignment process. Both Becky and I generally shoot with video lights and not strobes due to the number of pictures we take on a single dive. Regards, - brett Share this post Link to post Share on other sites
