Taxacom: digital camera question

Thu Aug 15 09:35:48 CDT 2024

Thanks Tony for that further feedback with respect to slide transparency.
Gives me a good comparative context. I also had one respondent using an
inexpensive Olympus TG-4 and camera with stacking capability (and sent me a
very nice example image). I had not thought about the latter capability
being within my price range, but I will make further inquiries.

Cheers, John

On Thu, Aug 15, 2024 at 12:06 AM Tony Rees <tonyrees49 at gmail.com> wrote:

> Hi John,
>
> Of course it depends on how big you would like to be able to print your
> results - e.g. at 300 DPI, a 1 MP image (approx.) would still print up to
> about 4 x 3 inches, a 4 MP image up to about  8 x 6 inches, and a 8 MP
> image up to about 12 x 9 inches before quality falls off... For many
> journal plates, they would be a composite of smaller images than (say) 10 x
> 8 inches, so small files would still get you there. On the other hand if
> you want something to go on the cover of "Nature" at large size, or just to
> create an archive of high quality images, large is definitely better!
>
> I was intrigued enough by this topic to look further into the old
> chestnut of "film vs digital" in which, as alluded to above, I believed
> that up to around 12 MP, 35mm film beat digital, and above that, the other
> way around (unless you go up to medium format etc.). I did a little test to
> see at what point quality loss became visible on a scanned - actually
> digitised with a micro 4/3 format, 20 MP resolution Olympus mirrorless SLR
> - 30 year-old slide, taken probably at 100 ISO in good light outdoors -
> copy put up at
> https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fcommons.wikimedia.org%2Fwiki%2FFile%3AMaritime_Museum_%252B_James_Craig_1990.jpg&data=05%7C02%7Ctaxacom%40lists.ku.edu%7C68e2871a17dd499824d708dcbd37a464%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638593293919092350%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=UcjzTdj%2FazJERK0xGE5jvfA057UdaIma%2FLdNyVcjJjA%3D&reserved=0
> , So, I digitised this at 20 MP including some of the slide mount; after
> cropping the latter off, I was left with 4,908 × 3,234 pixels (15.9 MP). I
> then down sampled this to 2 smaller sizes and enlarged a small portion of
> each image to see when quality loss would kick in. The answer seems to be
> that 8 MP is a little visibly worse than 16 MP, and 4 MP definitely worse,
> at least when "pixel peeping", see detailed enlargement comparison at
> https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpostimg.cc%2F2V6Rxtn9&data=05%7C02%7Ctaxacom%40lists.ku.edu%7C68e2871a17dd499824d708dcbd37a464%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638593293919092350%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=vAALx8snNBSGZ4mGRuLfQK%2FstIoRWCnknmAdhX1pnH4%3D&reserved=0 . So this tells me that maybe 16 MP of
> digital may well be needed to equate to a good slide (transparency), for
> those of us ancient enough to use this as a yardstick; however that may of
> course not be necessary unless you wish to print to very large sizes (would
> equate to 16 x 12 inches in this example).
>
> Apologies if the above is too much of a diversion for some, however in the
> overall context of "how much resolution is enough" for digital images I
> thought it might have some value...
>
> Regards to all - Tony
>
> Tony Rees, New South Wales, Australia
> https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fabout.me%2FTonyRees&data=05%7C02%7Ctaxacom%40lists.ku.edu%7C68e2871a17dd499824d708dcbd37a464%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638593293919092350%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=sxRkUgRah1Q03ftCBrsCn2HwKbeajI%2F88XtqvXWGGlo%3D&reserved=0
>
>
> On Thu, 15 Aug 2024 at 11:34, John Grehan via Taxacom <
> taxacom at lists.ku.edu> wrote:
>
>> Thanks Tony and Paulo, as well as an off-line respondent. It looks like I
>> will be able to afford up to 18 megapixels. As for the microscope - yeah,
>> you get what you pay for. But there is no way I can afford what I see in
>> university or museum facilities. But right now I have a microscope that is
>> over 50 years old (Kyowa - Japan) and used a small hand held digital
>> camera
>> which sometimes produced some barely adequate images. So at least I will
>> now be better off to some degree. Through the kindness of a couple of
>> university and museum colleagues I have been able to get stacked images
>> for
>> some important dissections.
>>
>> Cheers, John
>>
>> On Wed, Aug 14, 2024 at 6:17 PM Paulo Buckup <buckup at acd.ufrj.br> wrote:
>>
>> > Hi John,
>> >         To achieve 300 dpi, each square inch in the final page requires
>> > 90,000 pixels. So, a full letter size page (or equivalent in PDF)
>> requires
>> > over 8 megapixels. Allowing for some loss caused by cropping blank space
>> > around your specimen, you need at least a 10 megapixel camera for a full
>> > page image.
>> >         Keep in mind that if you do any resizing or rotation of the
>> final
>> > image, the relationship between the pixels in the original camera sensor
>> > and
>> > the final image is lost, and the quality is severely reduced. So, if
>> you do
>> > rotating or resizing in photoshop you will need a 40 megapixel camera to
>> > avoid individual pixel blurring.
>> >         In my experience the "cheap" microscope cameras do not meet
>> > traditional publication requirements (but will be accepted for
>> publication
>> > in open access journals by careless editors, mostly because PDFs are
>> only
>> > evaluated using monitors that have a resolution way below the 300 dpi
>> > standard).
>> >
>> > Cheers,
>> >
>> > Paulo Buckup
>> > Museu Nacional, UFRJ
>> > Brazil
>> > -----Mensagem original-----
>> > De: Taxacom [mailto:taxacom-bounces at lists.ku.edu] Em nome de John
>> Grehan
>> > via
>> > Taxacom
>> > Enviada em: quarta-feira, 14 de agosto de 2024 11:45
>> > Para: taxacom <taxacom at mailman.nhm.ku.edu>
>> > Assunto: Taxacom: digital camera question
>> >
>> > Hope someone on Taxacome has microscope camera expertise that can help
>> me
>> > with a question concerning digital camera capability meeting publication
>> > needs. I am looking at buying a 'cheap' (less than $1,000 US) dissecting
>> > microscope and digital camera through Amscope. They have cameras ranging
>> > from 1 to 20 megapixels, but I have no idea how that relates to dpi
>> where
>> > publications usually require at least 300 dpi. Can anyone clue me in on
>> how
>> > to know what megapixel size will likely work to give me a sharp enough
>> > image
>> > for publication? Currently looking at a 5 megapixel camera which brings
>> the
>> > setup well within my limits whereas 10 megapixel goes just over.
>> > Any enlightenment much appreciated. I am a total moron when it comes to
>> > digital camera tech.
>> >
>> > Thanks.
>> >
>> > John Grehan
>> >
>> > --
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