For some reason, super-telephoto lens manufacturers are still not shipping lenses with Arca-compatible lens feet. This means most buyers are immediately searching for a replacement lens foot featuring an Arca-Swiss dovetail that pairs nicely with the quick-release clamp on their ball head or gimbal. If you’re a Sony shooter using either the Sony 400mm f/2.8 GM or the Sony 600mm f/4 GM, there are two standard options from Kirk Photo and Really Right Stuff. I purchased both options, so this article discusses the pros and cons. In the end, there was one clear winner, and I’ll explain why.
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A Must: QD Compatible
The QD (quick detach) system is a standard that came from the firearms industry and has now been widely adopted by the third-party camera and lens plate manufacturers such as Kirk and RRS. This system is a great way to quickly release a camera strap from a camera body or super-telephoto lens. You can buy a camera strap with the QD hardware already attached to it, like the Blackrapid Sport X QD, or convert an existing strap to work with QD plates using this QD adapter. I love this system and consider it a must-have feature on any super-telephoto lens replacement foot I buy. The RRS and Kirk Photo feet for Sony’s big lenses have this feature.
Kirk Photo or RRS Lens Foot?
Both Kirk Photo and RRS make exceptional products. I have lost count of the items I’ve purchased over the years. When it comes to lens feet, I usually don’t have a preference between the two, but I often end up with a Kirk Photo foot because they tend to be first to market with new solutions when new lenses are released. It also doesn’t hurt that the Kirk lens feet are usually cheaper than the RRS equivalent.
Kirk LP-67 Lens Foot
The Kirk LP-67 lens foot is compatible with the Sony 400mm f2.8 GM and my 600mm f/4 GM. It is made of black anodized 6061-T6 aluminum and features a QD socket on the bottom. When I first needed a foot for my Sony 600mm lens, the Kirk LP-67 was what I purchased. Unfortunately, while I do like the short height of this foot, I quickly ran into trouble with its design.
As you can see in the photos, there’s a gap in the Arca-Swiss rail to accommodate the mounting screws for the lens foot. Aft of this gap, there is another small section of the dovetail, but you can have difficulties if you plan to clamp the foot in this area. The balance point of the Sony 600mm f/4 GM lens, with a camera body attached, falls right around this area. The balance point for the Sony 400mm f/2.8 GM with a gripped body and an attached teleconverter (thus equalizing its weight with the 600mm) also falls right around this area.
The situation will vary depending on your specific quick-release clamp, but in many cases, the actual clamping area you can use is diminished with this design. Additionally, if you use a Flexshooter head, you’re in even more trouble. The Flexshooter quick-release mechanism’s unique design means you must carefully try to align one part of the clamp with the small rear section of the dovetail on the Kirk lens foot. If you miss it, your precious super-telephoto lens will barely be attached to the Flexshooter head. I disliked this dovetail design, so I ditched the Kirk foot and moved on to the RRS alternative.
Really Right Stuff LCF-103 Lens Foot
The RRS LCF-103 lens foot is made from Type II Black Anodized 6061-T6 aluminum and is slightly more expensive than the Kirk LP-67. Significantly, the dovetail extends along the entire length of the lens foot, so you won’t have any issues using it with a Flexshooter head, and you’ll always have a wider clamping area with other styles of Arca quick-release clamps. As a bonus, I also found the more rearward position of the QD socket on the RRS foot to be better balanced when carrying my 600mm lens.
I typically don’t have strong opinions about the question of Kirk vs. RRS regarding Arca-compatible lens feet. I’ll happily buy either one, depending on what’s available when I need it. I initially chose the Kirk lens foot for my Sony 600mm f/4 GM but quickly realized this particular foot has some unusual shortcomings. A gap in the dovetail, right around the balance point, makes clamping less sturdy than it could be when used with most quick-release clamps. That gap also makes it dangerously difficult to use with a Flexshooter head, which is becoming an increasingly popular choice of head amongst wildlife photographers.
If you’re a Sony shooter using the 400mm or 600mm GM lenses, you should buy the Really Right Stuff LCF-103 head instead. This foot has a continuous dovetail along its length, and you’ll have no difficulties clamping the lens at the balance point. The marginal price difference between the two options should not be considered when your goal is to safely clamp a lens worth upwards of $10,000.
This review is not a blanket statement about all Kirk Photo lens feet compared to RRS feet. As far as I know, the Kirk foot for the Sony 400mm f/2.8 and 600mm f/4 foot is the only one with this strange, problematic gap in the dovetail. I have a Kirk foot on my Nikon Z 800mm lens, my Sony 200-600mm G lens, and the Nikon Z 400mm f/4.5. These are all great, and I do generally recommend them.
Where to Buy
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