For knife photography, I'm a fan of Sony cameras. It's because of the lens. The vast majority of cameras these days come with a plastic lens.... even some of the ultra high dollar cameras. Some of Sony's cameras do to....but if just have to ensure you read that specs to ensure a glass lens. In the Sony brand, look for "Carl Zeiss" and it will be a quality glass lens.......makes a huge difference. I currently own/use a cyber-shot dsc-hx200v, mainly because this camera has a "mode" dial on it..... and two of the modes are "easy", meaning that everything from light and color correction, to focus is taken care of..... I just have to get the knife positioned correctly in the frame, and be careful not to shake the camera (it MUST be on a tripod) when pressing the shutter button. Look up Sony DSC-H200 on ebay, and you can find them for less than $300. I've only purchase one new camera for knife photos, and that was a Nikon, that got returned within a week. I paid over $800 for it, and it couldn't take any better knife pics then the Sony DSC-200. Later I discovered that the Nikon I'd purchased was indeed a plastic lens, and every image I took with it turned out with a slight yellowish ting.....something that I have notice with any plastic lens camera I've used.
Don't let yourself get wrapped around the axle about the megapixels..... when you upload to the web, which is were most of your images will be going, the DPI get reduced to less then 100 anyway, to make the image "lite" enough for fast loading and not hogging up room on your website server. This camera give you enough megapixels to print image is Hi-Def, but also takes great pics for what you will mostly be doing.....web based stuff.
The camera is only about 20% of taking good knife pics..... the remaining 80% is lighting and background color/type. You MUST have a lighting tent to consistently take good knife pics. I recommend a "cube": https://www.amazon.com/Neewer-Shooting-Diffusion-Backdrops-Photography/dp/B00GKGGICC/ref=sr_1_3?dchild=1&keywords=photo+light+tent+cube&qid=1604239422&sr=8-3
Plus lighting like: https://www.amazon.com/Neewer-Profe...ords=photography+lights&qid=1604239616&sr=8-9
And the MOST important thing, that is so often overlooked, the proper background, both color and texture. If you look at my photos, most of them "pop" mainly because I have figured out the correct color and texture/material for backgrounds. That is most often a medium blue color, in the materials that is used for matting photos/potraits. :
I'll get some pics later today of my photo booth and how it's setup. This color of blue, and the texture is what works best for me.....
Another trick I've learned, if the camera has it, try using the "portrait" setting..... if the background is right, it will give a slight blur to the background, and make the knife look like it's more "forward" in the image.
Good, simple image editing software is a most too. For years I have been using Miscrosoft Image Suite to do a lot of editing. I think it was discontinued in 2006, but I keep it on my home server, and keep loading/using it.
Two others that also get a lot of use from me are.... https://engelmann.com/en/optimize-photos-simply-good-pictures/
I am certainly no professional photographer, but I've tried enough things to figure out what works for me, and what doesn't. I would guess that with a camera, light tent, lights, and associated gear, you can expect to spend about $400-$500 or so to get started (that is if you buy a used camera like the Sony DSC series.) But considering professional photos are around $200+ per photo these days, with a bit of practice/learning, you get a return on your money quickly.