Picked up a very nice copy of the Tamron 35-150 f2-2.8, and have been testing it on a variety of jobs paired with a Z8, ranging from studio headshots for a magazine, to a contemporary dance performance downtown, and today shooting a wedding with it.
I had picked it up because I'd read glowing reviews on sharpness and potential as a one camera and lens solution fast paced jobs like weddings. I had also heard of the flaring issues in backlit environments, which was a concern because with daytime environmental portraits I often position the sun behind the subject, but wanted to see for myself.
Prior to getting the 35-150, I had been using the 24-120 f4 combined with a 50 1.8 S on a second body, and they perform great as a pair. Fast autofocus, razor sharp wide open, and 24mm is useful for weddings where you're often in cramped environments. I've found the S lens design to be remarkably resistant flaring and loss of contrast in backlit conditions.
In terms of sharpness, center of frame wide open the 35-150 is acceptably sharp, but on the Z8 it is a little soft even stopped down to f4. It's less noticeable on the Z6iii, and still completely acceptable for paid work, but I was a little disappointed.
Autofocus is works great. For events/weddings I usually use either the medium square with eye-detect, or 3D tracking depending on the composition of the shot. I was able to get my SS up to 1/1000 for the dance performance and I had no issues getting keepers even with myself and the subjects moving around a ton. The dance job was even more challenging because they were wearing full black bodysuits with mirrored sculptures attached to them, so face detect was completely ineffective!
Flaring is enough of an issue that I am selling it on, and going back to the 24-120 f4 S. I used the 35-150 for editorial portraits in studio, and the brief was a pure white background. I carefully metered the background and flagged the bg lights with v-flats, and the loss of contrast from the backlighting of the background was immediately apparent in Capture One. Once I dialed down the background lights a little the contrast loss/hazing went away for the most part, but still a bummer because I've used the 24-120 f4 S with strong sun behind the subject with no issues with loss of contrast.
From a handling standpoint, I found the zoom to be a little stiff, and a little awkward depending on my hand position. I got used to it after a few hours of usage, but it's of course not nearly as comfortable as the 24-120 f4 for long shoots. I also found that for the dance performance that 35mm felt a little too tight. I ended up putting a 14-30 f4 on my Z6iii for the wide shots.
I am going to use it for a wedding today, and I think that will decide whether I am keeping it or not. It's a great lens if you don't need to get too wide for events and you're careful about strong backlighting. Anyways, just my two cents
I'd say after this wedding today, that it's a great lens for the ceremony, reception, toasts, first dance, candids later in the day especially. Today was a little overcast when we were doing outdoor formal portraits with the couple, and it had no issues with flaring, and the extra 30mm over the 24-120 on the tele end is very useful outdoors. I think the 24-120 f4 S and 35-150 could actually be somewhat complimentary in a wedding kit even though they seem to overlap in some ways, but for general event work the 24-120 f4 would be more than sufficient in my opinion. At higher ISO you don't notice the wide open softness as much, but it is noticeably softer than the 24-120 f4 and 24-70 f2.8 S wide open.
Also got to use my new Godox V100 a lot during the reception and first dance in the evening, and the TTL works great, on par with the Profoto A10 that's usually my go-to for events. It did seem a little magenta, but not enough that it's an issue. I think it's pretty easy to unscrew the cover on the fresnel and add a small piece of color correction gel if it bugs you enough. I love that you can charge the battery with just a USB-C cord.
