National collection of aerial photography

I have found it useful to search areas not online or for different dates for coverage already online. You can't see the actual photos just a map with a rough outline of every other or every third frame. My interest is Scotland and the UK and I have found it very useful but due to the number of frames I want to look at I can only afford low quality (72 dpi or A5) scans. These can sometimes be utterly useless but I have had some success.

As far as being worth it? For my use I would say yes as for the extra £20 I have ordered around 100 extra low res scans of which about 10% have solved a problem. If your targets would show on a scan that can't be enlarged greater than A5 then you might get some results but you will have to bracket suspect areas. Luckily extra frames from the same run are a fraction of the price of the initial frame but you can't do this without the finding aids. I haven't looked at Europe in this respect but I suspect there may be more obliques that aren't available online.

As far as viewing the scans available online I tend to view neighbouring frames by increasing or decreasing the number in the web address, assuming there is a neighbouring frame of course. I prefer frames to mosaics as these tend to have joins on the areas of interest, rather like maps

I was just looking to see if anything has been added to NCAP that makes it worth renewing my subscription. Most recent additions seem to have been 1960s and later but there are some 1954 Project ROBIN images of East Germany that might interest some people.