Tips to enhance the sharpness of the Canon EF 75-300mm Lens?

[Awpii]

So I bought this lens, which I've now come to known might be the worst Canon lens ever made, and while my photos are the sharpest at f/8, it's just painful.

I shoot wildlife photography and mostly birds for that matter, so I could really use the extra brightness smaller bigger apertures could provide when using faster shutter speeds, so I was wondering if there was *literally anything* I could do to make this lens just a tad bit sharper? 

Thanks in Advance!

[Do keep in mind, I live in Argentina, it's downright impossible for me at the moment to buy a better lens, the economic situation is dire and imports are scarce, so I'm afraid buying a new lens is just out of the question]

[Awpii]

This is a photo I took at f/5.6, as you can tell if you zoom in, it's very soft despite being properly focused.

[janesbenth1]

This is a photograph I took with an aperture of f/5.6; if you enlarge it, you will notice that the image is somewhat fuzzy even though the focus is spot on. 

[FloridaDrafter]

I have the EF 75-300mm f/4-5.6 II USM and used it for a few months while I decided on which lens to get. It came as a kit with either an XSi or T4i, I just don't remember. Anyway, from time to time I go back to those images and re-edit. It's been many years since I used that lens.

I use Digital Photo Professional 4 (DPP 4) to clean them up. The Digital Lens Optimizer in the Lens Correction panel does a decent job on my older lenses. I assume other programs will do this to a degree, but Canon knows Canon lenses better than anyone and I get good results. The image attached shows you where to find DLO and how to download the profile for whichever EF 75-300 lens you have (you don't say in your post).

I also sometimes run them through Topaz Sharpen AI if DPP doesn't do the job to my satisfaction, but it costs $$ where DPP 4 is free. As mentioned, images taken with this lens can be made better in post, whether it's DPP, Topaz, or PhotoShop. I mainly use DPP because it's free and I don't need any more tools for my bird photography than what DPP offers 😊

**Edit: I forgot to mention that DLO is only available to Raw images and will not work with JPeG, so I hope you are shooting Raw.

Newton

[Waddizzle]

What camera body are you using?  What are you trying to photograph?

I have gotten fairly decent results using a T5 and the EF 75-300mm lens.  (I forget which version of the lens I had.)  Here is what I used to do, beginning with using it outdoors on sunny days, or using a tripod under different conditions.

I discovered I got the best results shooting at f/8 with a minimum shutter speed of 1/800.  It also helps to have steady hands and to keep your elbows tucked in close to your body.  NO chicken wings allowed!  Besides, when your elbows are sticking out you run the risk of someone bumping into you and causing you to drop the camera.

I have found the biggest flaw with the lens are the AF motors, and not so much the optics.  As the camera focuses the lens, it may tell the lens to stop.  The AF motors stop moving, but not instantaneously. They may undershoot or overshoot the mark, which causes a soft image.  My sharpest photos with the EF 75-300mm were all manually focused.

[krahe]

I never thought about using manual focus. With all the noisy and spinning parts, it is a bit like having a Transformer mounted on the front of my camera compared to, say, my EF-M 55-200mm.

[ebiggs1]

First you need to get Canon's editing software DPP4 if you have not already done so. Second you need to be using raw format for taking photos. These two are mandatory. Period. You will apply lens correction as you import to your computer. Once a lens is made there is nothing you can do to increase its IQ but there are things you can do to get the best you can from it. Raw and DPP4 will help that.

Second you can't make extreme crops or enlargements. You just can't and that is a factor for any lens. Your lens is pretty limited to how much you can crop and still maintain good IQ. Your only solution for that is get closer to your subject in the first place.

You already know good techniques for shooting so no need to go over that again. But reminder, keep the ISO low as possible. SS as high as possible. Use One shot and not Ai-servo. Use just the center focus point too. And always shoot raw, never ever jpeg. The other camera settings you can set what ever as you wish as you will set them in permanently in DPP4.

[Tronhard]

It is going to be a challenge to improve past the potential of the lens to deliver performance.  There are applications available that will use AI algorithms to massage the resulting image, but they are not free.  DPP4 comes free with Canon cameras, and as my colleagues say, it has some features to provide corrections but not likely to the same level as the paid-for software.
There are several programs that are free to do post-processing and one or more of them may offer some improved features, these include:
Photopea:  Free, does not install on your computer but is accessed through its webpage.  It is quite powerful and has good tutorials available for its use.

The others are outlined in the following article:
Five Free, Open-Source Photo Editors To Try in 2023 (photographylife.com)

Definitely shoot in RAW if you are not already doing so, as you can impose much greater changes to  your images.   You can then save the resulting images as JPG or DNG files.