[Tudor97]

Im looking into getting one of these and I use my built in flash alot on my K-50 and im wondering if either of these lens cause a shadow when use the popup flash? I know the Sigma 18-35 did, so id like see if I can get answer before I buy one so I can save myself time/money if it won't suit my needs. Thanks!

[krazny]

The Tamron 17-50 causes a shadow when used with a k-5.

Although this can be minimized if you remove the hood.

I assume these dimension numbers are valid.

Sigma: 91.8mm x 83.5mm / 3.6 in. x 3.3 in

Tamron: 2.9 x 3.2" (74 x 82mm)

Side by side if you scroll down
https://www.the-digital-picture.com/Reviews/Tamron-17-50mm-f-2.8-XR-Di-II-Lens-Review.aspx

[Tudor97]

The Tamron 17-50 causes a shadow when used with a k-5.

Although this can be minimized if you remove the hood.

I assume these dimension numbers are valid.

Sigma: 91.8mm x 83.5mm / 3.6 in. x 3.3 in

Tamron: 2.9 x 3.2" (74 x 82mm)

Side by side if you scroll down
Tamron SP AF 17-50mm f/2.8 XR Di II LD IF Lens Review

Thanks for the info, I was afraid that would be the case due to the length or the wide filter size.

[ramseybuckeye]

Yes, The Sigma 17-50 will block part of the built on flash on the K -50, don’t know about the 17-70.

[mhoule418]

The Sigma 17-70 will also show some shadow when used with the built in flash.

[35mmfilmfan]

Isn't the answer not to use the pop-up flash ? A separate shoe-mounted flash should be usable with most lenses, in bounce mode.

[Kozlok]

It will be less than the 18-35, but if you use flash you will want a hot shoe mounted one.

[Tudor97]

Isn't the answer not to use the pop-up flash ? A separate shoe-mounted flash should be usable with most lenses, in bounce mode.

Yes but I prefer to keep my camera bag light and I don't like camera getting supper heavy either. Weight is a major factor for me, if my camera gets to heavy I don't take as good of handheld shots than if my setup stays under 1000 grams or so.

[mhoule418]

if my camera gets to heavy I don't take as good of handheld shots

The picture might not be good either because there is shadow created by the lens hood!

Also consider the lens weight... For sure the Sigma 17-70 is not small.
My preferred kit is : K-3 or K-5ii (with battery grip) + Sigma 17-70, so adding a small flash is just increasing the weight, but it balances well (for me).

The Pentax AF 200FG may be a very good option to consider :

• small and not too heavy
• cheap
• bring more power than the built-in unit

[peggers]

Im looking into getting one of these and I use my built in flash alot on my K-50 and im wondering if either of these lens cause a shadow when use the popup flash? I know the Sigma 18-35 did, so id like see if I can get answer before I buy one so I can save myself time/money if it won't suit my needs. Thanks!

I'm interested in another aspect of this question (Also using Pentax k5). By using a Sigma lens, is it true to say that some of the functions of an external Pentax flash will be not available? I've noticed that when using a Sigma 18-200 lens with a Pentax flash the results are far from consistent. Exposures will vary quite a lot. I have noticed that when using the Pentax 18-55 lens that all of a sudden the results when using the Pentax lens give perfect exposures almost all of the time

[mikesbike]

I'm interested in another aspect of this question (Also using Pentax k5). By using a Sigma lens, is it true to say that some of the functions of an external Pentax flash will be not available? I've noticed that when using a Sigma 18-200 lens with a Pentax flash the results are far from consistent. Exposures will vary quite a lot. I have noticed that when using the Pentax 18-55 lens that all of a sudden the results when using the Pentax lens give perfect exposures almost all of the time

As to the shadow from the built-in flash, this is because the size of the lens is causing it to be partially in the way of the flash output. Pentax does make a neat little hot shoe flash that has WR construction, and is not costly. It is so small it can easily be carried in a jacket pocket or takes up very little room in a camera bag. It also has more power than any bill-in flash of my acquaintance. But if the photography is takingrlce outside in bright daylight, and only some fill-flash is needed, there will probably be no detectable shadow from just the regular built-in flash.

The above is an interesting question. Indeed, lenses do feed info back to the camera, and some 3rd party lenses might be somewhat deficient in this regard. OTOH, I have numerous lenses by Pentax and 3rd party, yet have not noticed a discrepancy. Not to say it doesn't exist. But one thing the flash system is supposed to do is modify its flash angle according to the FL of the lens, yet there is a limitation for this. 55mm is well within that limitation, but a FL far greater, certainly 200mm, will not be reached, so the flash output will be more dissipated beyond the framing.

[mhoule418]

I've noticed that when using a Sigma 18-200 lens with a Pentax flash the results are far from consistent. Exposures will vary quite a lot. I have noticed that when using the Pentax 18-55 lens that all of a sudden the results when using the Pentax lens give perfect exposures almost all of the time

Well, not being an expert using flash, I suspect your problem is the “far subject” distance. When used at 200mm, the light produced by your flash is probably not reaching the subject, so “inconsistency” may be observed.

I may be wrong, but this is my though.

Edit
Oups! I stopped reading after peggers’s comment.
mikesbikes just said it too.

[Tudor97]

The picture might not be good either because there is shadow created by the lens hood!

Also consider the lens weight... For sure the Sigma 17-70 is not small.
My preferred kit is : K-3 or K-5ii (with battery grip) + Sigma 17-70, so adding a small flash is just increasing the weight, but it balances well (for me).

The Pentax AF 200FG may be a very good option to consider :

• small and not too heavy
• cheap
• bring more power than the built-in unit

Im beginning to realize for me its hard to beat any of the Pentax limited prime lens. They fit everything I need but they are pricey is the only downside.

[telum]

Well the plastic-fantastic 35mm and 50mm are very good as well, weights next to nothing and can often be used indoors without flash because they are fast F/2.4.

Especially the 35 has found good use for me indoors, whereas the 50mm often has bit too much reach..