Some days ago I received the Fotodiox EF-GFX adapter after reading a mix of reviews on the Internet about other adapters like the TECHART, KIPON or Viltrox. None of the reviews were conclusive, going from “I could use it only once”, or “it doesn’t detect any of my lenses”. So, I just told myself, “Let’s buy the one that doesn’t have reviews”.

After using it for some time I have mix feelings, not only with the adapter but with the quality of the pictures taken with the adapter. I know that the resolution resolved by old EF lenses either Canon/Sigma/Tamron will not be the same compared with my native GF lenses, but still, I just don’t want to get rid of some of them because I still use my Canon gear time to time. This entry is more a real field test than a chart one, is more about how I felt using the adapter, it’s pros and cons and maybe help you to take a decision.

Here are some pictures of how the camera looks with the adapter attached to it

Samples

The images are at the maximum aperture allowed by the lens and the adapter (not all them). That last note is important as the adapter doesn’t allow you to open the aperture on some lenses above F2.8, for example on my Sigma 105mm I couldn’t set the aperture to F1.4.

Canon EF 24mm-105mm F4:

Terrible, vignette at all focal lengths and apertures, a lot of color cast, softness, CAs, distortion, etc. The adapter gave me a lens error message once, removing and putting it back solved the issue. In general, I do not recommend this lens to pair with your GFX 100 unless you are looking for this effect on your pictures.

Canon EF 100mm Macro F2.8:

This lens performed better than expected. The main issue I had was that after taking a picture, for an unknown reason, messes the focus, this is especially bad on macro photography if you want to focus stack. You can see that there is no vignette at lower apertures.

Canon EF 50mm F1.4:

I do not like this lens, I feel is so poorly designed that it feels like a scam from Canon. I will not test it as you shouldn’t use this lens, never.

Sigma 105mm Art F1.4:

One big drawback of this lens on the EF mount on combination with the adapter is that I couldn’t set it to f/1.4. Slight vignette at 2.8, no vignette after 5.6. Sharp on the center of the frame and slight softness at wider apertures. In general a solid lens, I don’t know if the adapter for Nikon works well with the adapter and can work at 1.4

Sigma 14mm-24mm F2.8:

I had some problems at the beginning as the camera kept reporting Lens Error.

We can see that on the center of the frame the sharpness and contrast are good, on the edges of the frame is bad at 24mm and terrible at 14mm. There is slight to no vignette on 24mm and the considerable vignette at 14mm. Pictures were taken from the same spot, handheld at 1/125s f/2.8 ISO 3200.

Tamron 70mm-200mm F2.8:

Sharp enough on the center of the image, borders are soft. Vignette at all focal lengths and apertures. The adapter was able to recognize it without any issue and with good light, the focus was fast and accurate. Cheaper than the GFX 250mm, it doesn’t have the same focal length either quality.

I’m impressed with the Sigma 105, if Fotodiox updates the adapter to able to step the lens down to 1.4, it would be a serious option for low light situations. The lens doesn’t render the same amount of detail on the borders, but it is close, really. I would assume that at 1.4 the result would be different. The Sigma at 2.8 is brighter than the GF at 2.0.

I own some RF glass that sadly I can’t use with the adapter, and I don’t know if I would ever be able to adapt those lenses as the flange distance is too short on the RF system.

Conclusions

Pros:

• All my EF lenses work.

• Lens error can happen but it is not common.

• Really well-made adapter, it feels solid and professional, not just a piece of metal in front of the mount.

• A/P and 35mm/Medium format modes on the adapter.

Cons:

• On AF-C mode, autofocus hunts a lot.

• GF side of the mount is super tight, way too tight, it is impossible to remove the adapter without a lens attached to it.

• The macro lens was not usable because of the need to adjust the focus after each shot.

• The release button for the EF mount is on the opposite of the GFX one.

• Manual focus doesn’t zoom using the EVF neither the back LCD while you move the focus ring. This only happens with native GF lenses.

• Some of the lenses are not properly detected and you can’t open them to their maximum aperture. I have confirmed this with Fotodiox support team, it is sad, because in average is a solid adapter and Sigma lenses outperform Canon EF equivalents.

• Price. It is an expensive adapter.

Should you buy it?

• If you have a large collection of Canon EF lenses, yes, it is worth.

• If you want to use the adapter for macro photography with your EF 100 macro f2.8, don’t buy it.

• If you have a large amount of fast EF non-Canon lenses, no, don’t buy it unless Fotodiox update the firmware and start support them. Imagine spending $6000 on an Otus lens and not be able to step it down to 1.4.

I have ordered the Viltrox. after checking the GFX facebook group.

Update

I got the Viltrox adapter and it works perfect with my Sigma 105. I have to say I’m just impressed by this lens, there is just a slight vignetting at 1.4 but the image covers the whole sensor. It is not as sharp as my 110 F2, but is a lens designed for 35mm and you can use it 1.4, and the equivalent dof is 0.95 and is way brighter than the 110 even at F2.

I’ll have to check other sigma lenses and how they perform on the GFX.