What limits burst mode duration?

The camera buffer (fast internal memory) fills up as the camera shoots faster than it can write to the memory card. Once the buffer is full, the burst rate drops to the sustained rate, limited by the card write speed. Faster cards and larger buffers allow longer bursts.

Does file format affect burst depth?

Yes significantly. JPEG files are much smaller than RAW, so more fit in the buffer. RAW+JPEG writes both formats, using even more buffer space. Shooting compressed RAW or lossy RAW can increase buffer depth by 30-50% over uncompressed RAW.

What card write speed do I need?

For professional burst shooting at 10-20 fps with RAW files (50MB each), you need at least 90 MB/s write speed. CFexpress Type B cards can write at 400+ MB/s. UHS-II SD cards write at 90-250 MB/s. Faster cards clear the buffer faster, giving you more sustained shooting time.

What is sustained shooting rate?

The sustained rate is the continuous shooting speed once the buffer is full. It equals the card write speed divided by the file size. For example, a 90 MB/s card with 50MB RAW files gives a sustained rate of 1.8 fps — much slower than the initial burst rate.

PhotoCalcs

Burst Mode Calculator — Burst Duration & Image Count

Calculate how long you can shoot in burst mode before the buffer fills, and the sustained shooting rate.

Burst Rate

Camera continuous shooting speed

Buffer Depth

Frames before buffer full

File Size per Image

RAW file size

Card Write Speed

Memory card write speed

File Type

RAW, JPEG or both

How We Calculate This

This calculator models the camera buffer and card write pipeline:

Burst Duration

Burst duration = buffer depth (frames) / burst rate (fps)

Buffer Clear Time

Clear time = (total data - data written during burst) / card write speed

Sustained Rate

Sustained fps = card write speed / file size

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates based on standard optical and photographic formulas. Results may vary with specific equipment.