Guide to DSLR Camera Buying: What to Look For | Match Mount First

The buyer who leaves happy wrote down two things first: the mount their lenses use and the sensor size they need. The DSLR market is mature — current manufacturer pages still list the bodies below, but new beginner-first releases have slowed, so spec verification matters more than ever.

Which Mount Does The Camera Use?

The mount is the first filter, and getting it wrong wastes the most money. Nikon’s current DSLRs use the Nikon F mount — D3500, D500, D7500, D780, D850, and D6. Canon’s mount specifics are model-dependent, so check each model’s own page. Buy lenses labeled for your body’s mount only — a lens that seats but wasn’t built for that system costs you autofocus, metering, or both.

DX/APS-C Or FX/Full-Frame?

Nikon labels this directly: D3500 and D7500 are DX; D780, D850, and D6 are FX. DX bodies are smaller and cheaper to build a system around; FX bodies carry a larger sensor and higher-end performance. Nikon states DX models have a focal-length equivalent of roughly 1.5x relative to FX, so the same lens frames differently. Check format before buying glass.

Resolution lives inside that decision: from the Nikon D6 at 20.8 MP to the Nikon D850 at 45.7 MP and Canon EOS 5DS R at 50.6 MP. More megapixels isn’t automatically better — several bodies sit at similar or lower resolution but serve different jobs.

What Do Autofocus, Burst Rate, And ISO Buy You?

• Autofocus: Nikon D500 lists 153 AF points; Canon EOS 5DS R lists 61.
• Burst rate: D500 shoots 10 fps, D3500 up to 5 fps, EOS 5DS R up to 5.0 fps. Action and wildlife reward the higher number.
• ISO: D500 covers 100-51200; Canon EOS 90D lists up to 25,600. Wider range helps in low light, but sensor format matters as much.

Weight counts too: the Canon EOS 6D weighs about 755 g with battery and card, the EOS 600D near 570 g.

How Should You Match The Body To Your Shooting?

1. Confirm the mount and buy lenses labeled for it only.
2. Check sensor format before buying glass — DX and FX frame the same lens differently.
3. Verify the features you need: the D500 leans on AF points and frame rate, the D780 and D850 on FX sensors, the EOS 90D on resolution and ISO.
4. If you print large, crop heavily, or shoot action, prioritize resolution, AF coverage, and burst rate over a newer model number.

One caveat: the official pages cited here show specifications, not consistent US street prices, so check regional availability and current pricing before committing. If budget decides, our roundup of affordable DSLR bodies worth considering narrows the field. Canon’s camera buying guide groups the decision around optical viewfinders, fast performance, and lens, flash, and accessory options — a framework that works regardless of brand.

Buy the mount and sensor format that fit your work, verify the AF and burst numbers against your subject, and the model number stops mattering nearly as much as it seemed.