Quick answer
If your lens won't zip or slides around, match the case to the lens's actual length and filter size rather than its focal length. The Tamrac MX5379 fits lenses up to 8.5 inches long with an 82mm filter, while the Sigma soft case is dedicated to the 105mm f/2.8 DG DN Macro Art and any lens up to 7 inches high.
Why focal length alone misleads you
Two 100mm lenses can differ by inches once you add a hood, tripod collar, or adapter. The Sigma case is built around one specific macro lens, so its 7-inch height limit is a precise ceiling for that shape. The Tamrac MX5379 uses a longer 8.5-inch body and an 82mm filter ceiling, which suits larger telephoto or zoom lenses that the Sigma case cannot swallow.
Measure your lens with the hood reversed and any collar removed, then compare that number to the case's internal limit. If the lens exceeds the limit, no amount of padding will make the case close safely.
Protection versus convenience
The Tamrac uses 600D Ripstop PolyTek nylon with closed-cell foam and a weather flap, so it resists abrasion and light rain during transport. The Sigma soft case uses a padded design aimed at scratches and impacts during storage or travel, without the same weather sealing.
The Tamrac also adds a carry handle, belt loop, and M.A.S. modular attachment, which helps if you want the case on your belt or strapped to a larger bag. The Sigma case is simpler and lighter, which suits a dedicated macro kit that lives in a backpack.
Diagnose your fit problem
- Symptom: the case won't close or the lens bulges: Measure your lens length with the hood reversed and compare it to the case limit: 7 inches for the Sigma soft case, 8.5 inches for the Tamrac MX5379. Also check the filter size against the Tamrac's 82mm ceiling. If either number exceeds the limit, stop and choose the larger case. A case that needs force will not protect the lens.
- Symptom: the lens slides around inside: A loose fit usually means the case is oversized for your lens. The Sigma case is shaped for the 105mm macro and will hold it snugly; a generic case may not. If you need one case for several lenses, accept some movement or use a padded insert. Snug is safer than roomy for a single lens.
- Symptom: you need weather protection or belt carry: The Tamrac MX5379 adds a weather flap, carry handle, belt loop, and M.A.S. attachment. The Sigma soft case does not list these features. If you shoot in rain or want the case on your belt, choose the Tamrac; if the case stays in a bag, the Sigma is sufficient. Match the carry method to how you actually travel.
- When to stop and choose another option: If your lens is longer than 8.5 inches or has a filter size above 82mm, neither case fits. Look for a larger lens case or a lens pouch instead. A pouch offers less padding but more flexibility for oversized lenses. Do not buy either case if your lens exceeds both limits.
Product facts
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Sigma Soft Lens Case for 105mm f/2.8 DG DN Macro Art Lens: Soft, padded design dedicated to the Sigma 105mm f/2.8 DG DN Macro Art lens, compatible with any lens up to 7 inches high. If you own that macro lens, this case is a direct fit and avoids the guesswork of generic sizing.
Sigma Soft Lens Case for 105mm f/2.8 DG DN Macro Art Lens
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Tamrac MX5379 M.A.S. X-Large Lens Case: Fits lenses up to 8.5 inches long with an 82mm filter size, with closed-cell foam padding and a weather flap. Choose this when your lens is longer or wider than the Sigma case allows, or when you need weather resistance and belt carry.
Tamrac MX5379 M.A.S. X-Large Lens Case
