I set out to improve on the model's interiors. While I could get long DOF consistently outdoors, interiors still tended toward more blurring than I liked. But what I got from this attempt was a fairly different model altogether. Instead of considering it v1.5, I bumped it to 2.0.
Most notably, you can get consistent results in the target aesthetic (dramatic light and color with long DOF) with minimal prompting. Previously, you needed to write elaborate descriptions of your backgrounds to have them rendered in detail. But after including my latest additions to the training dataset, the model seems to have had an aha! moment and now understands its real purpose: always give us a detailed background.
Prompt for photographic scenes, don't worry overly much about how detailed you are, and enjoy the results.
As always, I'll gladly hear feedback for how it may still be improved.
notes for previous versions:
in Forge, please enable 'FP16 LoRA mode'
Use the word 'Photography' in your prompt: This model is prone to generate illustrations - really nice ones! - if you don't emphasize 'photography' enough. Be sure to prompt clearly for photographs! For fantasy and sci-fi scenes I begin and end prompts with photo terms.
If you want long depth of field/in-focus background: describe your background. Just write up some unique characteristics about what's back there - you'll get more focus on it.
Unlike with most other approaches taken with Flux, this won't mean you need to abandon cinematic/professional photo styles. Things can look both epic and have long depth of field. You can push this model toward snapshot or analog style images, though it's better done with a specific LoRA aimed at such.
If you want a blurred background: describe a foreground subject and refer to the background as sparsely and generically as possible. It will give you a focus on the subject and blur the background most of the time. Or reduce the strength of or don't use this LoRA, LOL. It's got positive impact outside of DOF so for photo prompts, I'm using it by default.
More then DOF: The primary motivation for the LoRA is depth and background detail - but even if you're prompting for a photo with an explicitly shallow DOF, this model brings improved realism of lighting, coloring, and texture as you can see in the comparison below (better viewed full-size at this imgur link) 
I started by training Flux on the same dataset as used for the SDXL model, Eldritch Candid Photography - that didn't yield pleasing results at all. So I changed the dataset a bunch, reduced the noise texture a ton, and modified the color/tonal edits. This produced a very nice Beta model.
But I didn't think the imposed tone and grain were doing as much service to this model as to the inspiration XL model. So, I trained a new model on the same dataset (very long DOF images) without any processing to them. On its own, images output from it were kind of harsh and austere looking. So I merged that with the beta model and got a really nice v1.0
But this still wasn't quite what I was looking for. So I tried a few other approaches and merge techniques before deciding on a simple curves adjustment to my dataset to heighten contrast and achieve a consistent dramatic lighting across them all. This one all on its own was close to the final target! But I tested a bunch of simple merges with my various models and settled on what is v 1.2 - I expect to be the final state of this thing for Flux.1 D
Probably final version. Stronger contrast, more neutral color tones, more dramatic lighting, sharper backgrounds.
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