Lens laws

[Journeyman]

Hello, I am beginning to seem like a serial questioner.

The answers to which lens is most successful for a given camera and subject seems to be almost unlimited.

My question relates to lenses used for bird photography and the ability to gain a sharp focus. My photos shows that the focus can be very sharp, just not focused on the birds.

A 600mm lens on a full frame camera is just that, 600mm. Surrounded by an enormous amount of magnifying lens glass. The quality of the photos is therefore appropriately high and sharp. Does this suggest that a prime lens offers clearer shots than a zoom lens?

A 400mm lens on a Canon crop frame camera is effectively a 640mm lens. With lesser amount of glass the photo is a little less sharp etc.

I have Canon EOS 90D, the best lens I can reach is an EF100-400mm 4.5-5.6 L II. A great lens in any circumstance. However my shots don't come out with the tack sharp focus I would like to achieve. I have attached a couple of photos with complete with exif data. (1 Tamron 18-400 X bird on the wing and 1 Canon 100-400 two birds hanging around).

Would a 70-300 produce a better image? It would be 480mm crop frame size and a 1.4 converter would take it out to 672mm.

The search for a better image and reliable technique goes on.

Thank you for entering the chat, Journeyman


Egret focus 4-12.jpgIbis focus 4-12.jpg