Which lens should I get next?

Ckrol wrote:

I recently bought a Panasonic gx7 and the Panasonic 14mm f2.5, and I also have a couple of old Olympus OM lenses (28mm f2.8 and 50mm f1.4) I'm looking to get another lens the question I have is wether I should get the Panasonic 20mm 1.7 or the Olympus 45mm f1.8. Which lens would be a better buy for me (I mostly do street photography and landscapes)

IBIS in your Panasonic GX7 is first generation 7 years old technology.

Thus, as regards the 45ish prime lens, the OIS in Panasonic 42.5 f1.7 will help you to get better results in low light than the non stabilized Oly 45mm.

Both lenses are very close in size and optical performance. I have the Pany 42.5 and its OIS is very efficient even on my non stabilized G7 and GM5.

You dont mention whether your two Olympus lenses are 4/3 or legacy 35mm film lenses. Film era lenses are MF only when adapted to M43, 4/3 Olympus lenses can be AF when using the OEM Olympus 4/3 to M43 adapter (which is not cheap).

I suggest you buy a cheap generic M43 adapter (price rates from 20 to 30 €/$) to check what will be your photographic experience using your adapted legacy lenses.

But if you want to really enjoy your GX7, AF modern lenses are a must, whether zoom or primes.

I have 8 Panasonic lenses, 4 zooms (12-32, 12-60 f3.5-5.6, 14-140 and 35-100 f4-5.6), 3 f1.7 primes (20, 25 and 42.5) and the 25mm f2.5.

They all deliver sharp and contrasty pictures and their AF is OK on all my Pany bodies, including the GM5 which I guess must have an AF technology close to your GX7.

IMO, any M43 lens will deliver good enough IQ, almost undistinguishable at normal viewing size or printing. What matters most is the angle of view (=focal length) and maximum aperture (low light and subject separation).

Primes and high end lenses also deliver more native out of camera contrast and clarity, but post processing can improve the rendering of entry level zooms to almost as good looking results.

The 20mm f1.7 AF-S performance is OK, even in dim light on contrasty targets. IMO, most complaints about its subpar AF applies to early M43 bodies.

Beware it cannot use AF-C, because it focuses by moving the whole lens. On my Pany bodies, when using the 20mm, AF-C is grayed and the camera asks you to switch to AF-S.

The Panasonic 20mm rendering is very pleasing, almost like high end pro lenses, with a lot of contrast. You easily get a kind of 3D pop in your photography.

There is no OEM hood, but it is very resistant to flare.

The field of view is equivalent to 40mm in 35mm film cameras, just a tad wider than the nifty-fifty standard lenses in film cameras, which is very versatile, and f1.7 allows for low light shooting and also some bokeh.

I enjoy using it fully open in museums. I am rather a zoom shooter and it is the prime I use the most when sightseeing.

The 14mm f2.5 is a very small and light lens, whith a very efficient AF design. The wider angle of view, equivalent to 28mm on 35mm film cameras, is, IMO, the most useful for street photography, close to the angle of view of most smartphones: wide enough for fast framing in street photography or for group photography indoors, but not too wide to distort the perspective. There is no OEM hood but it has a good resistance to flare.

The 14mm field of view is also convenient for landscapes or cityscapes but, because of the pancake design, there is some field curvature which will be visible in some scenes at widest apertures: far away corners will be slightly out of focus when the center will be focused to infinity or closer. Yet it can only be an issue when viewed at pixel size. Closing to f4 will avoid this issue.

The 25mm f1.7 is a cheap "plastic wonder", with good optical performance and sold with an OEM hood. It is an alternative to the 20, with excellent AF-S and AF-C performance, but bigger and lacking the outstanding rendering of the 20.

The 42.5 f1.7 is an excellent lens, with fast AF-S and AF-C, sharpness across the frame and a lot of contrast. The in-lens OIS is much more efficient than Panasonic first generation IBIS in GX7/GX8. I enjoy it for subject isolation, portrait and also low light video.

As other posters said, you might also enjoy a transtandard zoom lens. The 12-32 and 12-60 f3.5-5.6 are optically very good for entry level lenses, and excellent AF performance.

As they are usually sold as kit lenses in bundles with a new body, you can easily find cheap new "white box" o,es (dekitted by pro sellers, with legal guarantee), or second hand.

They both deliver their best performance at their wide end, which is the cheapest and most convenient way to get a 24mm film era equivalent angle of view (there is a noticeable difference between 12 and 14 in M43).

The 12-32 collapses to a very tiny and light size when not in use, easy to add to any bag or jacket pocket. Extended for use, it is still compact and thus is very unobstrusive for street shooting. The focal range (24 to 64 FF equivalent) makes for a versatile enough go-around lens, and the OIS allows shooting hand held in low light. Its only limitation is it has no MF ring: manual focusing is possible, with all focusing aids, but must be driven from the camera body.

The 12-60 goes to medium telephoto (120 mm equivalent), which makes it very versatile, it can be your only lens for travel or sightseeing. It is light and rather compact, with good haptics and a more rugged build than the 12-32. However it is a bigger lens that may catch people's attention while street shooting.

If you dont mind loosing the 12-14 range, there are also different 14-42 f3.5-5.6 OIS Pany kit lenses, and the 14-140 f3.5-5.6 which is better  than it should be expected from a 10X superzoom, and is the most convenient travel all in one zoom.

There are equivalent or better zooms offering from Olympus but either non stabilized or much bigger and more expensive like the 12-100 f4.