How I rate thermals
Every thermal I review is scored the same way, on the same six categories, each out of 10. This page is the full set of rules, so you can see what a score means and judge for yourself whether you agree with it.
The short version
- Three categories are scored from a number I measured or looked up: the laser rangefinder, the price and the battery life.
- Three are my judgment, scored against written descriptions: image quality, controls and gut feeling.
- The overall score is the plain average of the six. Nothing is weighted.
- If I couldn't test something, that category is left blank and left out of the average. The review says so.
- Who paid for the thermal never changes a score. Each review says whether I bought it, borrowed it, or was sent it.
The six categories
Image quality
My judgment. I pick the description that matches what I saw. An odd score means it fell between two of them.
| 2 | Grainy. An animal at 100 yards is a warm blob and the background is flat grey. |
|---|---|
| 4 | Animal shape is clear at 100 yards. Only tree lines show behind it. Noise or lag when panning. |
| 6 | Legs, ears and tail are distinct at 100 yards. Fences and terrain show. A little noise. |
| 8 | Legs, ears and tail are distinct at 200 yards. Grass, brush and fence posts show detail. Clean when panning. |
| 10 | Fine detail at 200 yards, such as the edge of the fur. The background looks close to a photo. No noise. |
Laser rangefinder
Scored from a number: farthest reliable range on an animal. Amounts in between are scored in proportion. A thermal with no rangefinder scores 1.
| 1 | 0 yd |
|---|---|
| 2 | 200 yd |
| 4 | 300 yd |
| 6 | 450 yd |
| 8 | 700 yd |
| 10 | 1000 yd |
Controls
My judgment. I pick the description that matches what I saw. An odd score means it fell between two of them.
| 2 | I needed the manual in the field. The buttons cannot be told apart by feel. |
|---|---|
| 4 | Usable after several nights. Frequent wrong presses in the dark. |
| 6 | Learned in a night or two. An occasional wrong press. |
| 8 | Buttons are distinct by feel. Common jobs take one press. Mistakes are rare. |
| 10 | I ran everything by feel on the first night, with gloves on. |
Price
Scored from a number: price you would pay today. Amounts in between are scored in proportion. A lower price scores higher.
| 1 | $10,000 |
|---|---|
| 2 | $8,000 |
| 4 | $6,000 |
| 6 | $4,000 |
| 8 | $2,500 |
| 10 | $1,500 |
Battery life
Scored from a number: run time, full to dead. Amounts in between are scored in proportion.
| 1 | 1 hr |
|---|---|
| 2 | 2 hr |
| 4 | 3 hr |
| 6 | 4 hr |
| 8 | 6 hr |
| 10 | 8 hr |
Gut feeling
My judgment. I pick the description that matches what I saw. An odd score means it fell between two of them.
| 2 | I would not hunt with it again. |
|---|---|
| 4 | I would use it if it was all I had, but I would not buy it. |
| 6 | A solid scope. I would be fine owning it, but would not go out of my way for it. |
| 8 | I would buy it with my own money. |
| 10 | I would pick it over everything else I have used. |
Scoring version 2. If the rules change, the version changes and earlier thermals are rescored from the numbers I recorded.
What a rating can't tell you
Image quality, controls and gut feeling are one hunter's judgment, formed mostly on coyotes in open farm country in Wisconsin. Thermal performance also changes with the weather, so a scope tested on a cold, dry night has an easier job than one tested in fog. Read the review alongside the score: it says how long I had the thermal and what conditions it saw.
Questions
If you think a score is wrong, or want a thermal tested, email Sales@defiantsolutionsco.com or leave a comment on the review.