Lossy DNG shows strong visible differences but JPG not, is this a bug?

hello,

 

i tried out lossy dng format lot of pictures.

for pictures can't find visible differences.

but found pictures noticible visible differences between lossless , lossy dng.

it seems lossy dng format has problems dark pictures small light sources example

the stars in dark sky or red lights of aeroplane in dark sky.

i have example can see red security lights of great antenna on top of mountain.

surprisingly extreme example jpg versions looks better lossy dng version of source lossless dng.

 

here cropped jpg lossless dng (file size 10877kb):

between jpg , lossless dng file no visible difference.

and here jpg lossy dng (file size 13261kb):

 

between jpg , source lossy dng file no visible difference.

the source of both dng files nef file nikon d7100.

also interessting is, excample file size of lossy dng is  greater lossless dng. seems crasy imho.

 

i surprised, jpg result is better lossy dng case.

perhaps there hidden bug in lossy dng conversion process.

 

i hope adobe can in this. if need original nef file let me know.

today tried out lightroom 5 beta.

i wanted know, whether above behaviour of dng lossy conversion still there.

unfortunately is.

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