Awesome Northrup videos!

ata3001 wrote:

Tony Northrup has no credibility! In one of his recent videos, he talks trash about UV/lens protection filters & how these cheap "plastic" filters hurt image quality. First of all, does anyone actually make plastic filters?

Then in the same video, he takes a 50mm lens & totally destroys the front element by scratching it up then shoots with it, commenting on how the scratches really haven't hurt the image quality. He then goes on to say that buying used lenses with scratched front glass can be quite a bargain.

This is the same guy who started off in this same video stating to NOT use UV/lens protection filters because they hurt image quality.

How can he have any credibility when he puts out videos like this?

Link:

https://www.youtube.com/watch?v=YcZkCnPs45s&index=17&list=PLwIVS3_dKVpsyZJ-BhsCHwTj8Y6PEAurc

Well cheap UV filters can cause ghosting, glare, decreased contrast and can introduce other aberrations. Basically the main problem that it causes (that doesn't apply to a scratched front element) is that it introduces another glass surface over the entire image that can have internal reflections and the glass may not be flat (which causes waviness in the bokeh and changes the flare pattern).

https://www.lensrentals.com/blog/2017/06/the-comprehensive-ranking-of-the-major-uv-filters-on-the-market/

Of course if you get a decent multicoated filter, then the effect is negligible.

A scratched front element can also decrease contrast (if bad enough) and will affect flare when in direct sunlight. But small scratches would have almost no effect on IQ.

https://www.lensrentals.com/blog/2016/12/front-element-lens-protection-revisited/

https://petapixel.com/2015/07/02/how-much-does-a-scratch-affect-the-quality-of-a-lens/